[PATCH] fix UP proc.c compile warning

The hyper-threading in /proc/cpuinfo patch introduced a compile warning
under UP.

Fixed thus.

arch/i386/kernel/cpu/proc.c

@@ -17,7 +17,6 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 	 * applications want to get the raw CPUID data, they should access
 	 * /dev/cpu/<cpu_nr>/cpuid instead.
 	 */
-	extern int phys_proc_id[NR_CPUS];
 	static char *x86_cap_flags[] = {
 		/* Intel-defined */
 	        "fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce",
@@ -77,6 +76,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 		seq_printf(m, "cache size\t: %d KB\n", c->x86_cache_size);
 #ifdef CONFIG_SMP
 	if (cpu_has_ht) {
+		extern int phys_proc_id[NR_CPUS];
 		seq_printf(m, "physical id\t: %d\n", phys_proc_id[n]);
 		seq_printf(m, "siblings\t: %d\n", smp_num_siblings);
 	}