src: Remove unused <arch/cpu.h>

Change-Id: I1112aa4635a3cf3ac1c0a0834317983b4e18135a
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50172
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/intel/skylake/cpu.c

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
-#include <arch/cpu.h>
 #include <console/console.h>
 #include <device/device.h>
 #include <device/pci.h>