fbcon: trivial optimization for fbcon_exit

Break out as soon as we find a mapped entry con2fb_map.
Signed-off-by: NWang YanQing <udknight@gmail.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/console/fbcon.c

@@ -3547,8 +3547,10 @@ static void fbcon_exit(void)
 			"no"));
 
 		for (j = first_fb_vc; j <= last_fb_vc; j++) {
-			if (con2fb_map[j] == i)
+			if (con2fb_map[j] == i) {
 				mapped = 1;
+				break;
+			}
 		}
 
 		if (mapped) {