[PATCH] m68k: broken constraints on mulu.l

Too permissive constraint on mulu.l - the first argument should not be
an a-register.  Fixed by replacing "g" with "dm"; with older gcc we got
lucky and it had never attempted mulu.l %a0, %d1:%d0.  These days it
does, with predictable objections from as(1).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>