Actually return %ebx value from cpuid_ebx()

Change-Id: I75f8f942950cad94439a10e389490ecfdd9272fe
Signed-off-by: Jonathan A. Kollasch <jakllsch@kollasch.net>
Reviewed-on: http://review.coreboot.org/880
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/arch/x86/include/arch/cpu.h

@@ -91,8 +91,8 @@ static inline unsigned int cpuid_ebx(unsigned int op)
 
 	__asm__("mov %%ebx, %%edi;"
 		"cpuid;"
+		"mov %%ebx, %%esi;"
 		"mov %%edi, %%ebx;"
-		"mov %%edi, %%esi;"
 		: "=a" (eax), "=S" (ebx)
 		: "0" (op)
 		: "ecx", "edx", "edi");