benet: Wait f/w POST until timeout

While PCI card faces EEH errors, reset (usually hot reset) is
expected to recover from the EEH errors. After EEH core finishes
the reset, the driver callback (be_eeh_reset) is called and wait
the firmware to complete POST successfully. The original code would
return with error once detecting failure during POST stage. That
seems not enough.

The patch forces the driver (be_eeh_reset) to wait the firmware
completes POST until timeout, instead of returning error upon
detection POST failure immediately. Also, it would improve the
reliability of the EEH funtionality of the driver.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Acked-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>