enic: increment devcmd2 result ring in case of timeout

Firmware posts the devcmd result in result ring. In case of timeout, driver
does not increment the current result pointer and firmware could post the
result after timeout has occurred. During next devcmd, driver would be
reading the result of previous devcmd.

Fix this by incrementing result even in case of timeout.

Fixes: 373fb087 ("enic: add devcmd2")
Signed-off-by: Sandeep Pillai <sanpilla@cisco.com>
Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>