drm: remove `const` attribute to hint at caller that they now own the memory

Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 120869e..64e41cf 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3113,7 +3113,7 @@
 	for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
 		struct drm_plane_state *state;
 		struct drm_plane *plane = &intel_plane->base;
-		const char *format_name;
+		char *format_name;
 
 		if (!plane->state) {
 			seq_puts(m, "plane->state is NULL!\n");