drm/exynos/fimd: signal frame done interrupt at front porch

VBLANK interrupt should be signalled as soon as scanout ends, front porch
is the best moment.
Signed-off-by: NAndrzej Hajda <a.hajda@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -243,7 +243,7 @@ static int fimd_enable_vblank(struct exynos_drm_crtc *crtc)
 			val |= VIDINTCON0_INT_FRAME;
 
 			val &= ~VIDINTCON0_FRAMESEL0_MASK;
-			val |= VIDINTCON0_FRAMESEL0_VSYNC;
+			val |= VIDINTCON0_FRAMESEL0_FRONTPORCH;
 			val &= ~VIDINTCON0_FRAMESEL1_MASK;
 			val |= VIDINTCON0_FRAMESEL1_NONE;
 		}