be2net: fix return status of some ndo methods

The netlink layer expects a -ve status value to be returned when a driver
ndo method encounters an error. The driver was directly passing the
error status returned by FW (a positive value) to the stack.
This patch fixes this by returning -EIO status when a FW-cmd reports an error.

Signed-off-by: Kalesh AP <kalesh.purayil@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>