AGESA F15tn: Move callouts into northbridge wrapper

There are currently too many things in the mainboard directories that
are really more suited to being in the northbridge / southbridge
wrappers.  This is a start at moving some of those functions down
into the wrappers.

Move the bios callback functions into the northbridge/amd/agesa/family15tn
directory from the mainboard directories.  These can still be overridden
by any mainboard just by updating the pointer in the callback table to
point to a customized version of the function.

Change-Id: Icefaa014f4a4abbe51870aee7aa2fa1164e324c1
Signed-off-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-on: http://review.coreboot.org/2169
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>
7 files changed