x86, cleanup: Remove obsolete boot_cpu_id variable

boot_cpu_id is there for historical reasons and was renamed to
boot_cpu_physical_apicid in patch:

 c70dcb7 x86: change boot_cpu_id to boot_cpu_physical_apicid

However, there are some remaining occurrences of boot_cpu_id that are
never touched in the kernel and thus its value is always 0.

This patch removes boot_cpu_id completely.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-8-git-send-email-robert.richter@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 85f69cd..3a683ea 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -169,7 +169,7 @@
 {
 #ifdef CONFIG_SMP
 	/* calling is from identify_secondary_cpu() ? */
-	if (c->cpu_index == boot_cpu_id)
+	if (!c->cpu_index)
 		return;
 
 	/*