drm/amd/display: fix documentation for dm_crtc_additional_color_mgmt()

warning: expecting prototype for drm_crtc_additional_color_mgmt().
Prototype was for dm_crtc_additional_color_mgmt() instead

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312141801.o9eBCxt9-lkp@intel.com/


Signed-off-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>