bna: Remove Unnecessary CNA Check

Change details:
 - ioc->cna is always set to 1 for eth functions, remove the check that
   asserts IOC is in CNA mode in bfa_ioc_firmware_lock() and
   bfa_ioc_firmware_unlock() in bfa_ioc_ct.c.

Signed-off-by: Rasesh Mody <rmody@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>