x86, AMD, NB: Use u16 for northbridge IDs in amd_get_nb_id

Change amd_get_nb_id to return u16 to support >255 memory controllers,
and related consistency fixes.

Signed-off-by: Daniel J Blueman <daniel@numascale-asia.com>
Link: http://lkml.kernel.org/r/1353997932-8475-2-git-send-email-daniel@numascale-asia.com


Signed-off-by: Borislav Petkov <bp@alien8.de>