drm/tilcdc: make tilcdc_mode_hvtotal() static

The function tilcdc_mode_hvtotal is local to the source and does not need
to be in global scope, so make it static.

drivers/gpu/drm/tilcdc/tilcdc_crtc.c:297:6: warning: no previous prototype for 'tilcdc_mode_hvtotal' [-Wmissing-prototypes]
 uint tilcdc_mode_hvtotal(const struct drm_display_mode *mode)
Signed-off-by: NXiongwei Song <sxwjean@gmail.com>
Signed-off-by: NJyri Sarha <jsarha@ti.com>

drivers/gpu/drm/tilcdc/tilcdc_crtc.c

@@ -272,7 +272,7 @@ static void tilcdc_crtc_set_clk(struct drm_crtc *crtc)
 				LCDC_V2_CORE_CLK_EN);
 }
 
-uint tilcdc_mode_hvtotal(const struct drm_display_mode *mode)
+static uint tilcdc_mode_hvtotal(const struct drm_display_mode *mode)
 {
 	return (uint) div_u64(1000llu * mode->htotal * mode->vtotal,
 			      mode->clock);