aacraid: do not activate events on non-SRC adapters

Only SRC-based adapters support the AifReqEvent function, so there is no
point in trying to activate it on older, non-SRC based adapters.  Doing
so lead to crashes on older adapters.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: Raghava Aditya Renukunta <RaghavaAaditya.Renukunta@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>