x86: use BUILD_BUG_ON() for the size of struct intel_mp_floating

Use BUILD_BUG_ON() instead of compile-time error technique with
extern non-exsistent function.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 70744e3..101b13c 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -686,13 +686,11 @@
 static int __init smp_scan_config(unsigned long base, unsigned long length,
 				  unsigned reserve)
 {
-	extern void __bad_mpf_size(void);
 	unsigned int *bp = phys_to_virt(base);
 	struct intel_mp_floating *mpf;
 
 	Dprintk("Scan SMP from %p for %ld bytes.\n", bp, length);
-	if (sizeof(*mpf) != 16)
-		__bad_mpf_size();
+	BUILD_BUG_ON(sizeof(*mpf) != 16);
 
 	while (length > 0) {
 		mpf = (struct intel_mp_floating *)bp;