drm/nouveau: use ALIGN instead of open coding it

CC: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nv50_instmem.c b/drivers/gpu/drm/nouveau/nv50_instmem.c
index f0dc4e3..de1f5b0 100644
--- a/drivers/gpu/drm/nouveau/nv50_instmem.c
+++ b/drivers/gpu/drm/nouveau/nv50_instmem.c
@@ -390,7 +390,7 @@
 	if (gpuobj->im_backing)
 		return -EINVAL;
 
-	*sz = (*sz + (NV50_INSTMEM_PAGE_SIZE-1)) & ~(NV50_INSTMEM_PAGE_SIZE-1);
+	*sz = ALIGN(*sz, NV50_INSTMEM_PAGE_SIZE);
 	if (*sz == 0)
 		return -EINVAL;