vxge: Remember to release firmware after upgrading firmware

Regardless of whether the firmware update being performed by
vxge_fw_upgrade() is a success or not we must still remember to always
release_firmware() before returning.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Acked-by: Ram Vepa <ram.vepa@exar.com>
Signed-off-by: David S. Miller <davem@davemloft.net>