[PATCH] net: stmmac: Fix signedness bug in stmmac_probe_config_dt()

[YueHaibing]

The "plat->phy_interface" variable is an enum and in this context GCC
will treat it as an unsigned int so the error handling is never
triggered.

Fixes: b9f0b2f634c0 ("net: stmmac: platform: fix probe for ACPI devices")
Signed-off-by: YueHaibing <yuehaibing at huawei.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index f32317fa75c8..b5b558b02e7d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -413,7 +413,7 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
 	}
 
 	plat->phy_interface = device_get_phy_mode(&pdev->dev);
-	if (plat->phy_interface < 0)
+	if ((int)plat->phy_interface < 0)
 		return ERR_PTR(plat->phy_interface);
 
 	plat->interface = stmmac_of_get_mac_mode(np);
-- 
2.17.1