drm/nv50: rename nv84_mpeg to nv50_mpeg

In preparation for adding 0x50 support.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/Makefile b/drivers/gpu/drm/nouveau/Makefile
index 7b3f23a..0583677 100644
--- a/drivers/gpu/drm/nouveau/Makefile
+++ b/drivers/gpu/drm/nouveau/Makefile
@@ -21,7 +21,7 @@
              nv40_grctx.o nv50_grctx.o nvc0_grctx.o \
              nv84_crypt.o \
              nva3_copy.o nvc0_copy.o \
-             nv40_mpeg.o nv84_mpeg.o \
+             nv40_mpeg.o nv50_mpeg.o \
              nv04_instmem.o nv50_instmem.o nvc0_instmem.o \
              nv50_evo.o nv50_crtc.o nv50_dac.o nv50_sor.o \
              nv50_cursor.o nv50_display.o \