octeontx2-af: Remove set but not used variable 'dev'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/marvell/octeontx2/af/cgx.c: In function 'cgx_fwi_event_handler':
drivers/net/ethernet/marvell/octeontx2/af/cgx.c:257:17: warning:
 variable 'dev' set but not used [-Wunused-but-set-variable]

It never be used since introduction in
commit 1463f382 ("octeontx2-af: Add support for CGX link management")
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/af/cgx.c

@@ -254,7 +254,6 @@ static inline bool cgx_event_is_linkevent(u64 event)
 static irqreturn_t cgx_fwi_event_handler(int irq, void *data)
 {
 	struct lmac *lmac = data;
-	struct device *dev;
 	struct cgx *cgx;
 	u64 event;
 
@@ -265,8 +264,6 @@ static irqreturn_t cgx_fwi_event_handler(int irq, void *data)
 	if (!FIELD_GET(EVTREG_ACK, event))
 		return IRQ_NONE;
 
-	dev = &cgx->pdev->dev;
-
 	switch (FIELD_GET(EVTREG_EVT_TYPE, event)) {
 	case CGX_EVT_CMD_RESP:
 		/* Copy the response. Since only one command is active at a