uboot-phytec

x86: Move qemu CPU fixup function into its own file

This function is specific to qemu so it seems best to keep it separate
from the generic code.

Move it out to a new file and update the condition to use if() instead of
 #ifdef

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>