x86: move cpu_exit_clear to process_32.c

Take it out of smpboot.c, and move it to process_32.c, closer
to its only user.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/numa_32.h b/include/asm-x86/numa_32.h
index a02674f..ed6c88e 100644
--- a/include/asm-x86/numa_32.h
+++ b/include/asm-x86/numa_32.h
@@ -2,6 +2,7 @@
 #define _ASM_X86_32_NUMA_H 1
 
 extern int pxm_to_nid(int pxm);
+extern void numa_remove_cpu(int cpu);
 
 #ifdef CONFIG_NUMA
 extern void __init remap_numa_kva(void);