bnx2x: Fix functionality of configuring vlan list

The check on return code of bnx2x_vfop_config_vlan0() would lead to error
handling flow as the return value indicating an existing pending ramrod would
be erroneously considered as an error.

Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>