drm: s/drm_crtc_get_hv_timings/drm_mode_get_hv_timings/

The function operates on modes, not CRTCs. Also move it into
drm_modes.[hc]. Spotted while reviewing CRTC docs.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170125062657.19270-15-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 03ac27b..4304988 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2367,7 +2367,7 @@ int __drm_atomic_helper_set_config(struct drm_mode_set *set,
 	if (ret != 0)
 		return ret;
 
-	drm_crtc_get_hv_timing(set->mode, &hdisplay, &vdisplay);
+	drm_mode_get_hv_timing(set->mode, &hdisplay, &vdisplay);
 
 	drm_atomic_set_fb_for_plane(primary_state, set->fb);
 	primary_state->crtc_x = 0;