pm3fb: fix sparse warning

Fix this sparse warning:

  drivers/video/pm3fb.c:543:3: warning: returning void-valued expression
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/pm3fb.c

@@ -539,8 +539,10 @@ static void pm3fb_imageblit(struct fb_info *info, const struct fb_image *image)
 		bgx = par->palette[image->bg_color];
 		break;
 	}
-	if (image->depth != 1)
-		return cfb_imageblit(info, image);
+	if (image->depth != 1) {
+		cfb_imageblit(info, image);
+		return;
+	}
 
 	if (info->var.bits_per_pixel == 8) {
 		fgx |= fgx << 8;