bnxt_en: initialize rc to zero to avoid returning garbage

rc is not initialized so it can contain garbage if it is not
set by the call to bnxt_read_sfp_module_eeprom_info. Ensure
garbage is not returned by initializing rc to 0.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -1591,7 +1591,7 @@ static int bnxt_get_module_eeprom(struct net_device *dev,
 {
 	struct bnxt *bp = netdev_priv(dev);
 	u16  start = eeprom->offset, length = eeprom->len;
-	int rc;
+	int rc = 0;
 
 	memset(data, 0, eeprom->len);