drm/radeon: Fold radeon_set_cursor() into radeon_show_cursor()

Reviewed-by: Grigori Goronzy <greg@chown.ath.cx>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --cc drivers/gpu/drm/radeon/radeon_cursor.c
Simple merge