hw/i386/pc: move shared x86 functions to x86.c and export them

Move x86 functions that will be shared between PC and non-PC machine
types to x86.c, along with their helpers.

Signed-off-by: Sergio Lopez <slp@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
8 files changed