drm/nouveau/dispnv04: fix build on powerpc
drm/nouveau/dispnv04: fix build on powerpc

align with mask code in overlay.c, Ben can clean the naming
up later if necessary.

Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs