[PATCH] siimage: enable interrupts on Adaptec SA-1210 card

The siimage driver proports to support the Adaptec SA-1210 SATA
controller.  However, at least some of those cards boot-up with their
interrupts disabled internally.  The siimage driver currently ignores
that fact, so that driver does not actually work with those cards.
This patch enables those interrupts on cards that need it.

[ This is implemented based on similar code in the libata-based
  sata_sil driver. ]

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>