x86: Fix override new_cpu_data.x86 with 486

We should set X86 to 486 before use cpuid to detect the cpu type, if
we set X86 to 486 after cpuid, then we will get 486 until cpu_detect
runs.

Signed-off-by: Wang YanQing <udknight@gmail.com>
Link: http://lkml.kernel.org/r/20130628144516.GA2177@udknight


Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>