cpu/mp_init: Fix microcode lock

Fix C code to match comment and assembly implementation.

Tested on Prodrive hermes:
The microcode spinlock is no longer used.

Change-Id: I21441299f538783551d4d5ba2b2e7567e152d718
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49304
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index 01c1d5f..c691c48 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -344,9 +344,9 @@
 	sp->microcode_ptr = (uintptr_t)mp_params->microcode_pointer;
 	/* Pass on ability to load microcode in parallel. */
 	if (mp_params->parallel_microcode_load)
-		sp->microcode_lock = 0;
-	else
 		sp->microcode_lock = ~0;
+	else
+		sp->microcode_lock = 0;
 	sp->c_handler = (uintptr_t)&ap_init;
 	ap_count = &sp->ap_count;
 	atomic_set(ap_count, 0);