drm/atmel-hlcdc: Make ->reset() implementation static

The atmel_hlcdc_crtc_reset() function is never used outside the file and
can be static. This avoids a warning from sparse.

Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c

@@ -387,7 +387,7 @@ void atmel_hlcdc_crtc_irq(struct drm_crtc *c)
 	atmel_hlcdc_crtc_finish_page_flip(drm_crtc_to_atmel_hlcdc_crtc(c));
 }
 
-void atmel_hlcdc_crtc_reset(struct drm_crtc *crtc)
+static void atmel_hlcdc_crtc_reset(struct drm_crtc *crtc)
 {
 	struct atmel_hlcdc_crtc_state *state;