ixgbe: Fix format string in ixgbe_fcoe.

cppcheck detected following warning in ixgbe_fcoe.c (warning) %d in format
string (no. 1) requires 'int' but the argument type is 'unsigned int'.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Tested-By: Jack Morgan <jack.morgan@intel.com>
Signed-off-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c

@@ -585,7 +585,7 @@ static int ixgbe_fcoe_dma_pool_alloc(struct ixgbe_fcoe *fcoe,
 	struct dma_pool *pool;
 	char pool_name[32];
 
-	snprintf(pool_name, 32, "ixgbe_fcoe_ddp_%d", cpu);
+	snprintf(pool_name, 32, "ixgbe_fcoe_ddp_%u", cpu);
 
 	pool = dma_pool_create(pool_name, dev, IXGBE_FCPTR_MAX,
 			       IXGBE_FCPTR_ALIGN, PAGE_SIZE);