[SCSI] aacraid: suppress two GCC warnings

Building src.o for a 32 bit system triggers two GCC warnings:
    drivers/scsi/aacraid/src.c: In function ‘aac_src_deliver_message’:
    drivers/scsi/aacraid/src.c:410:3: warning: right shift count >= width of type [enabled by default]
    drivers/scsi/aacraid/src.c:434:2: warning: right shift count >= width of type [enabled by default]

These warnings are caused by a right shift of 32. Use upper_32_bits() to
suppress them.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Mahesh Rajashekhara <Mahesh_Rajashekhara@pmc-sierra.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>