Fix the mac_scsi interrupt edge trigger on non-RBV PowerBooks. This doesn't appear to help my PowerBook 520 but the NetBSD source reveals that the PowerBook 500 series is different than the others.
Signed-off-by: NFinn Thain <fthain@telegraphics.com.au>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>