[PATCH] drm/mm: Fix support 4 GiB and larger ranges

bad argument if(tmp)... in check_free_hole

fix oops: kernel BUG at drivers/gpu/drm/drm_mm.c:305!

[airlied: excellent, this was my task for today].
Signed-off-by: NKrzysztof Kolasa <kkolasa@winsoft.pl>
Reviewed-by: NChris wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_mm.c

@@ -403,7 +403,7 @@ static int check_free_hole(u64 start, u64 end, u64 size, unsigned alignment)
 		unsigned rem;
 
 		rem = do_div(tmp, alignment);
-		if (tmp)
+		if (rem)
 			start += alignment - rem;
 	}