cpu/x86/mp_init.c: Don't overwrite the global variable per CPU

Global variables are located in .bss and not on the CPU stack.
Overwriting them a per CPU case is bound to cause race conditions. In
this case it is even just plainly wrong.

Note: This variable is set up in the get_smm_info() function.

Change-Id: Iaef26fa996f7e30b6e4c4941683026b8a29a5fd1
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51184
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/cpu/x86/mp_init.c

@@ -732,7 +732,6 @@ static void asmlinkage smm_do_relocation(void *arg)
 	 */
 #if CONFIG(X86_SMM_LOADER_VERSION2)
 	perm_smbase = smm_get_cpu_smbase(cpu);
-	mp_state.perm_smbase = perm_smbase;
 	if (!perm_smbase) {
 		printk(BIOS_ERR, "%s: bad SMBASE for CPU %d\n", __func__, cpu);
 		return;