be2net: remove BUG_ON() in be_mcc_compl_is_new()

The current code expects that the last word (with valid bit)
of an MCC compl is DMAed in one shot. This may not be the case.
Remove this assertion.

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