x86, xsave: 32/64 bit boot cpu check unification in initialization

Boot cpu id is always 0, thus simplifying and unifying boot cpu check.

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.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279651857-24639-3-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/cpu/common.c

@@ -1273,7 +1273,7 @@ void __cpuinit cpu_init(void)
 	/*
 	 * Boot processor to setup the FP and extended state context info.
 	 */
-	if (smp_processor_id() == boot_cpu_id)
+	if (!smp_processor_id())
 		init_thread_xstate();
 
 	xsave_init();