scsi: aacraid: Fix INTx/MSI-x issue with older controllers

commit 78cbccd3 ("aacraid: Fix for KDUMP driver hang")

caused a problem on older controllers which do not support MSI-x (namely
ASR3405,ASR3805). This patch conditionalizes the previous patch to
controllers which support MSI-x

Cc: <stable@vger.kernel.org> # v4.7+
Fixes: 78cbccd3

 ("aacraid: Fix for KDUMP driver hang")
Reported-by: Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>
Signed-off-by: Dave Carroll <david.carroll@microsemi.com>
Reviewed-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>