[PATCH v3] usb: musb: remove unused variable 'devctl'

[min.guo at mediatek.com]

From: Min Guo <min.guo at mediatek.com>

Remove unused 'devctl' variable to fix compile warnings:

    drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
    drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
    but not used [-Wunused-but-set-variable]

Signed-off-by: Min Guo <min.guo at mediatek.com>
---
changes in v3
suggested by Greg Kroah-Hartman:
Add a comment.

changes in v2
suggested by Alan Stern:
Add void before musb_read to indicate that the register MUSB_DEVCTL
was intended to be read and discarded.
---
 drivers/usb/musb/musbhsdma.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
index 0aacfc8be5a1..2a345b4ad015 100644
--- a/drivers/usb/musb/musbhsdma.c
+++ b/drivers/usb/musb/musbhsdma.c
@@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
 				musb_channel->channel.status =
 					MUSB_DMA_STATUS_BUS_ABORT;
 			} else {
-				u8 devctl;
-
 				addr = musb_read_hsdma_addr(mbase,
 						bchannel);
 				channel->actual_len = addr
@@ -336,7 +334,11 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
 						< musb_channel->len) ?
 					"=> reconfig 0" : "=> complete");
 
-				devctl = musb_readb(mbase, MUSB_DEVCTL);
+				/*
+				 * Some hardware may need to read the
+				 * MUSB_DEVCTL register once to take effect.
+				 */
+				(void)musb_readb(mbase, MUSB_DEVCTL);
 
 				channel->status = MUSB_DMA_STATUS_FREE;
 
-- 
2.18.0