linux-wandboard

ahci: Store interrupt value

Use a stored value for which interrupts to enable.  Changing this allows
us to selectively turn off certain interrupts later and have them
stay off.

Signed-off-by:  Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>