drm/savage: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

This patch fixes the following warnings:

drivers/gpu/drm/savage/savage_state.c:301:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/gpu/drm/savage/savage_state.c:438:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/gpu/drm/savage/savage_state.c:559:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/gpu/drm/savage/savage_state.c:697:8: warning: this statement may fall through [-Wimplicit-fallthrough=]

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enabling
-Wimplicit-fallthrough.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190129202005.GA25789@embeddedor

drivers/gpu/drm/savage/savage_state.c

@@ -299,6 +299,7 @@ static int savage_dispatch_dma_prim(drm_savage_private_t * dev_priv,
 	case SAVAGE_PRIM_TRILIST_201:
 		reorder = 1;
 		prim = SAVAGE_PRIM_TRILIST;
+		/* fall through */
 	case SAVAGE_PRIM_TRILIST:
 		if (n % 3 != 0) {
 			DRM_ERROR("wrong number of vertices %u in TRILIST\n",
@@ -436,6 +437,7 @@ static int savage_dispatch_vb_prim(drm_savage_private_t * dev_priv,
 	case SAVAGE_PRIM_TRILIST_201:
 		reorder = 1;
 		prim = SAVAGE_PRIM_TRILIST;
+		/* fall through */
 	case SAVAGE_PRIM_TRILIST:
 		if (n % 3 != 0) {
 			DRM_ERROR("wrong number of vertices %u in TRILIST\n",
@@ -557,6 +559,7 @@ static int savage_dispatch_dma_idx(drm_savage_private_t * dev_priv,
 	case SAVAGE_PRIM_TRILIST_201:
 		reorder = 1;
 		prim = SAVAGE_PRIM_TRILIST;
+		/* fall through */
 	case SAVAGE_PRIM_TRILIST:
 		if (n % 3 != 0) {
 			DRM_ERROR("wrong number of indices %u in TRILIST\n", n);
@@ -695,6 +698,7 @@ static int savage_dispatch_vb_idx(drm_savage_private_t * dev_priv,
 	case SAVAGE_PRIM_TRILIST_201:
 		reorder = 1;
 		prim = SAVAGE_PRIM_TRILIST;
+		/* fall through */
 	case SAVAGE_PRIM_TRILIST:
 		if (n % 3 != 0) {
 			DRM_ERROR("wrong number of indices %u in TRILIST\n", n);