mpt3sas: Added smp_affinity_enable module parameter.

Module parameter to enable/disable configuring affinity hint for msix
vector.  SMP affinity feature can be enabled/disabled by setting module
parameter "smp_affinity_enable" to 1/0.  By default this feature is
enabled. (smp_affinity_enable = 1 enabled).

Signed-off-by: Suganath prabu Subramani <suganath-prabu.subramani@avagotech.com>
Signed-off-by: Chaitra P B <chaitra.basappa@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>