[PATCH net-next] net: stmmac: xgmac: use const char arrays for string constants

[Simon Horman]

Jiri Slaby advises me that the preferred mechanism for declaring
string constants is static char arrays, so use that here.

This mostly reverts
commit 1692b9775e74 ("net: stmmac: xgmac: use #define for string constants")

That commit was a fix for
commit 46eba193d04f ("net: stmmac: xgmac: fix handling of DPP safety error for DMA channels").
The fix being replacing const char * with #defines in order to address
compilation failures observed on GCC 6 through 10.

Compile tested only.
No functional change intended.

Suggested-by: Jiri Slaby <jirislaby at kernel.org>
Link: https://lore.kernel.org/netdev/485dbc5a-a04b-40c2-9481-955eaa5ce2e2@kernel.org/
Signed-off-by: Simon Horman <horms at kernel.org>
---
 .../net/ethernet/stmicro/stmmac/dwxgmac2_core.c    | 69 +++++++++++-----------
 1 file changed, 34 insertions(+), 35 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index f196cd99d510..cbf2dd976ab1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -846,42 +846,41 @@ static const struct dwxgmac3_error_desc dwxgmac3_dma_errors[32]= {
 	{ false, "UNKNOWN", "Unknown Error" }, /* 31 */
 };
 
-#define DPP_RX_ERR "Read Rx Descriptor Parity checker Error"
-#define DPP_TX_ERR "Read Tx Descriptor Parity checker Error"
-
+static const char dpp_rx_err[] = "Read Rx Descriptor Parity checker Error";
+static const char dpp_tx_err[] = "Read Tx Descriptor Parity checker Error";
 static const struct dwxgmac3_error_desc dwxgmac3_dma_dpp_errors[32] = {
-	{ true, "TDPES0", DPP_TX_ERR },
-	{ true, "TDPES1", DPP_TX_ERR },
-	{ true, "TDPES2", DPP_TX_ERR },
-	{ true, "TDPES3", DPP_TX_ERR },
-	{ true, "TDPES4", DPP_TX_ERR },
-	{ true, "TDPES5", DPP_TX_ERR },
-	{ true, "TDPES6", DPP_TX_ERR },
-	{ true, "TDPES7", DPP_TX_ERR },
-	{ true, "TDPES8", DPP_TX_ERR },
-	{ true, "TDPES9", DPP_TX_ERR },
-	{ true, "TDPES10", DPP_TX_ERR },
-	{ true, "TDPES11", DPP_TX_ERR },
-	{ true, "TDPES12", DPP_TX_ERR },
-	{ true, "TDPES13", DPP_TX_ERR },
-	{ true, "TDPES14", DPP_TX_ERR },
-	{ true, "TDPES15", DPP_TX_ERR },
-	{ true, "RDPES0", DPP_RX_ERR },
-	{ true, "RDPES1", DPP_RX_ERR },
-	{ true, "RDPES2", DPP_RX_ERR },
-	{ true, "RDPES3", DPP_RX_ERR },
-	{ true, "RDPES4", DPP_RX_ERR },
-	{ true, "RDPES5", DPP_RX_ERR },
-	{ true, "RDPES6", DPP_RX_ERR },
-	{ true, "RDPES7", DPP_RX_ERR },
-	{ true, "RDPES8", DPP_RX_ERR },
-	{ true, "RDPES9", DPP_RX_ERR },
-	{ true, "RDPES10", DPP_RX_ERR },
-	{ true, "RDPES11", DPP_RX_ERR },
-	{ true, "RDPES12", DPP_RX_ERR },
-	{ true, "RDPES13", DPP_RX_ERR },
-	{ true, "RDPES14", DPP_RX_ERR },
-	{ true, "RDPES15", DPP_RX_ERR },
+	{ true, "TDPES0", dpp_tx_err },
+	{ true, "TDPES1", dpp_tx_err },
+	{ true, "TDPES2", dpp_tx_err },
+	{ true, "TDPES3", dpp_tx_err },
+	{ true, "TDPES4", dpp_tx_err },
+	{ true, "TDPES5", dpp_tx_err },
+	{ true, "TDPES6", dpp_tx_err },
+	{ true, "TDPES7", dpp_tx_err },
+	{ true, "TDPES8", dpp_tx_err },
+	{ true, "TDPES9", dpp_tx_err },
+	{ true, "TDPES10", dpp_tx_err },
+	{ true, "TDPES11", dpp_tx_err },
+	{ true, "TDPES12", dpp_tx_err },
+	{ true, "TDPES13", dpp_tx_err },
+	{ true, "TDPES14", dpp_tx_err },
+	{ true, "TDPES15", dpp_tx_err },
+	{ true, "RDPES0", dpp_rx_err },
+	{ true, "RDPES1", dpp_rx_err },
+	{ true, "RDPES2", dpp_rx_err },
+	{ true, "RDPES3", dpp_rx_err },
+	{ true, "RDPES4", dpp_rx_err },
+	{ true, "RDPES5", dpp_rx_err },
+	{ true, "RDPES6", dpp_rx_err },
+	{ true, "RDPES7", dpp_rx_err },
+	{ true, "RDPES8", dpp_rx_err },
+	{ true, "RDPES9", dpp_rx_err },
+	{ true, "RDPES10", dpp_rx_err },
+	{ true, "RDPES11", dpp_rx_err },
+	{ true, "RDPES12", dpp_rx_err },
+	{ true, "RDPES13", dpp_rx_err },
+	{ true, "RDPES14", dpp_rx_err },
+	{ true, "RDPES15", dpp_rx_err },
 };
 
 static void dwxgmac3_handle_dma_err(struct net_device *ndev,