bna: HW Interface Init Update

Change details:
 - Split the hw interface into common and asic specific to support new asic
   in the future.
 - Fix bfa_ioc_ct_isr_mode_set() to also include the case that we are already
   in the desired msix mode.

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