Let main menu scale (non-Android)

This fixes main menu not fitting for 800x600 (and lower resolutions) on PC builds

builtin/mainmenu/init.lua

@@ -139,11 +139,8 @@ local function init_globals()
 	tv_main:add(tab_credits)
 
 	tv_main:set_global_event_handler(main_event_handler)
-	if PLATFORM ~= "Android" then
-		tv_main:set_fixed_size(true)
-	else
-		tv_main:set_fixed_size(false)
-	end
+
+	tv_main:set_fixed_size(false)
 
 	if not (PLATFORM == "Android") then
 		tv_main:set_tab(core.setting_get("maintab_LAST"))