[SCSI] aacraid: Fix down_interruptible() to check the return value

Instead of ignoring the return value in aac_fib_send() return 2 to
indicate to the layers above that fib transmission was aborted due to
timeout.

Signed-off-by: Mark Salyzyn <aacraid@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>