octeontx2-af: Remove redundant initialization of variable pin

The variable pin is being initialized with a value that is never
read, it is being updated later on in only one case of a switch
statement.  The assignment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c

@@ -194,7 +194,7 @@ static int otx2_ptp_enable(struct ptp_clock_info *ptp_info,
 {
 	struct otx2_ptp *ptp = container_of(ptp_info, struct otx2_ptp,
 					    ptp_info);
-	int pin = -1;
+	int pin;
 
 	if (!ptp->nic)
 		return -ENODEV;