x86: intel: cougarcanyon2: Remove dead code

start.S does nothing and can be safely removed. Makefile is still being used
by the build system, so simply drop the rule from it.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>

board/intel/cougarcanyon2/Makefile

@@ -2,4 +2,4 @@
 #
 # Copyright (C) 2016, Bin Meng <bmeng.cn@gmail.com>
 
-obj-y	+= cougarcanyon2.o start.o
+obj-y	+= cougarcanyon2.o

board/intel/cougarcanyon2/start.S

-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * Copyright (C) 2016, Bin Meng <bmeng.cn@gmail.com>
- */
-
-.globl early_board_init
-early_board_init:
-	jmp	early_board_init_ret