posix file: Let the OS decide addresses to map to

Reverse the direction of the `Addr` parameter of Map(). We let mmap()
decide which address to use and return that. Given that we can set the
address for `MMIO_Range` instances during runtime, we shouldn't ever
have to force static addresses.

Change-Id: I35bfd65e7b471daae4f43a9233ce613c7f45891e
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/20552
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
3 files changed