fbdev: omapfb: Remove writeback deadcode

Value of enum parameter 'plane' is initialized in dss_init_overlays and
cannot take the value OMAP_DSS_WB. Function dispc_ovl_setup_common could
be called with this value of parameter only from dispc_wb_setup, which has
never been used and has been removed in commit 4f55bb0
("omapfb: Remove unused writeback code"). The code in the if-branch is
unreachable.

Remove unreachable branch.

Found by Linux Verification Center (linuxtesting.org) with SVACE static
analysis tool.

Signed-off-by: Leonid Arapov <arapovl839@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Author: SomeRandomToaster

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

@@ -2659,13 +2659,8 @@ static int dispc_ovl_setup_common(enum omap_plane plane,
 	row_inc = 0;
 	pix_inc = 0;
 
-	if (plane == OMAP_DSS_WB) {
-		frame_width = out_width;
-		frame_height = out_height;
-	} else {
-		frame_width = in_width;
-		frame_height = height;
-	}
+	frame_width = in_width;
+	frame_height = height;
 
 	if (rotation_type == OMAP_DSS_ROT_TILER)
 		calc_tiler_rotation_offset(screen_width, frame_width,