scsi: bfa: bfa_ioc: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases where
we are expecting to fall through.

Notice that, in this particular case, I replaced "!!! fall through !!!"
comment with "fall through" annotations, which is what GCC is expecting to
find.

Addresses-Coverity-ID: 146155 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Sudarsana Kalluru <Sudarsana.Kalluru@qlogic.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>