src/cpu/x86: Update/Add license headers to all files

Change-Id: I436bf0e7db008ea78e29eaeef10bea101e6c8922
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/18405
Tested-by: build bot (Jenkins)
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/cpu/x86/lapic/boot_cpu.c

@@ -1,3 +1,16 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
 #include <smp/node.h>
 #include <cpu/x86/msr.h>