aacraid: Change interrupt mode to MSI for Series 6

aacraid: Change interrupt mode to MSI for Series 6

This change always sets MSI interrupt mode for series-6 controller.

Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Murthy Bhat <Murthy.Bhat@pmcs.com>
Reviewed-by: Karthikeya Sunkesula <Karthikeya.Sunkesula@pmcs.com>
Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara@pmcs.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
(cherry picked from commit 9022d375bd22869ba3e5ad3635f00427cfb934fc)

Orabug: 25505509
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>