I moved it to a separate function which is safer.

This avoids problems with the linker reordering them and the
less useful PCI config space access methods taking priority
over the better ones.

Fixes some problems with broken MMCONFIG

Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>