treewide: Remove unused <cpu/x86/msr.h>

Change-Id: I187c2482dd82c6c6d1fe1cbda71710ae1a2f54ad
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64890
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/arch/x86/c_exit.S

@@ -1,10 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <arch/ram_segs.h>
-#include <cpu/x86/msr.h>
 #include <cpu/x86/cr.h>
 
-
 #if ENV_X86_64
 
 	/*