fdisk: use functions from pt-mbr.h

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: (dos) move pte specific function to dos.c

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: (dos) remove unnecessary function

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: (dos) remove inline function from header file

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: add mbr_get_partition()

Signed-off-by: Karel Zak <kzak@redhat.com>