be2net: fix a bug in UE detection logic

The ONLINE registers can return 0xFFFFFFFF on more than one
occassion. On systems that care, reading these registers could
lead to problems.

So the new code decides that the ASIC has encountered and error
by reading the UE_STATUS_LOW/HIGH registers. AND them with
the mask values and a non-zero result indicates an error.

Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>