omapfb: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/omap2/omapfb/dss/dispc.c

@@ -1905,6 +1905,7 @@ static void calc_vrfb_rotation_offset(u8 rotation, bool mirror,
 		if (color_mode == OMAP_DSS_COLOR_YUV2 ||
 			color_mode == OMAP_DSS_COLOR_UYVY)
 			width = width >> 1;
+		/* fall through */
 	case OMAP_DSS_ROT_90:
 	case OMAP_DSS_ROT_270:
 		*offset1 = 0;
@@ -1927,6 +1928,7 @@ static void calc_vrfb_rotation_offset(u8 rotation, bool mirror,
 		if (color_mode == OMAP_DSS_COLOR_YUV2 ||
 			color_mode == OMAP_DSS_COLOR_UYVY)
 			width = width >> 1;
+		/* fall through */
 	case OMAP_DSS_ROT_90 + 4:
 	case OMAP_DSS_ROT_270 + 4:
 		*offset1 = 0;

drivers/video/fbdev/omap2/omapfb/omapfb-main.c

@@ -893,6 +893,7 @@ int omapfb_setup_overlay(struct fb_info *fbi, struct omap_overlay *ovl,
 				/ (var->bits_per_pixel >> 2);
 			break;
 		}
+		/* fall through */
 	default:
 		screen_width = fix->line_length / (var->bits_per_pixel >> 3);
 		break;