drm/exynos: consider both case of vflip and hflip.

This patch considers both case of vflip and hflip.
If we want that the contents in buffer to be rotated to 180 degree,
then we can use h,vflip or 180 degree.

Changelog v2:
- added EXYNOS_DRM_FLIP_BOTH enum value to avoid build warnning.
Signed-off-by: Eunchul Kim <chulspro.kim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimc.c

@@ -1387,6 +1387,7 @@ static inline bool fimc_check_drm_flip(enum drm_exynos_flip flip)
 	case EXYNOS_DRM_FLIP_NONE:
 	case EXYNOS_DRM_FLIP_VERTICAL:
 	case EXYNOS_DRM_FLIP_HORIZONTAL:
+	case EXYNOS_DRM_FLIP_BOTH:
 		return true;
 	default:
 		DRM_DEBUG_KMS("%s:invalid flip\n", __func__);

drivers/gpu/drm/exynos/exynos_drm_gsc.c

@@ -1391,7 +1391,7 @@ static inline bool gsc_check_drm_flip(enum drm_exynos_flip flip)
 	case EXYNOS_DRM_FLIP_NONE:
 	case EXYNOS_DRM_FLIP_VERTICAL:
 	case EXYNOS_DRM_FLIP_HORIZONTAL:
-	case EXYNOS_DRM_FLIP_VERTICAL | EXYNOS_DRM_FLIP_HORIZONTAL:
+	case EXYNOS_DRM_FLIP_BOTH:
 		return true;
 	default:
 		DRM_DEBUG_KMS("%s:invalid flip\n", __func__);

drivers/gpu/drm/exynos/exynos_drm_rotator.c

@@ -513,6 +513,7 @@ static inline bool rotator_check_drm_flip(enum drm_exynos_flip flip)
 	case EXYNOS_DRM_FLIP_NONE:
 	case EXYNOS_DRM_FLIP_VERTICAL:
 	case EXYNOS_DRM_FLIP_HORIZONTAL:
+	case EXYNOS_DRM_FLIP_BOTH:
 		return true;
 	default:
 		DRM_DEBUG_KMS("%s:invalid flip\n", __func__);

include/uapi/drm/exynos_drm.h

@@ -171,6 +171,8 @@ enum drm_exynos_flip {
 	EXYNOS_DRM_FLIP_NONE = (0 << 0),
 	EXYNOS_DRM_FLIP_VERTICAL = (1 << 0),
 	EXYNOS_DRM_FLIP_HORIZONTAL = (1 << 1),
+	EXYNOS_DRM_FLIP_BOTH = EXYNOS_DRM_FLIP_VERTICAL |
+			EXYNOS_DRM_FLIP_HORIZONTAL,
 };
 
 enum drm_exynos_degree {