drm: Constify TV mode names

Make the mode names passed to drm_mode_create_tv_properties() const.

 drivers/gpu/drm/i2c/ch7006.ko:
-.rodata                       596
+.rodata                       664
-.data                        7064
+.data                        6992

 drivers/gpu/drm/nouveau/nouveau.ko:
-.rodata                      146808
+.rodata                      146904
-.data                        178624
+.data                        178528

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/nouveau/dispnv04/tvmodesnv17.c

@@ -32,7 +32,7 @@
 #include "hw.h"
 #include "tvnv17.h"
 
-char *nv17_tv_norm_names[NUM_TV_NORMS] = {
+const char * const nv17_tv_norm_names[NUM_TV_NORMS] = {
 	[TV_NORM_PAL] = "PAL",
 	[TV_NORM_PAL_M] = "PAL-M",
 	[TV_NORM_PAL_N] = "PAL-N",