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>
diff --git a/src/northbridge/amd/agesa/family15tn/Makefile.inc b/src/northbridge/amd/agesa/family15tn/Makefile.inc
index 121bf22..b0cf7ff 100644
--- a/src/northbridge/amd/agesa/family15tn/Makefile.inc
+++ b/src/northbridge/amd/agesa/family15tn/Makefile.inc
@@ -17,4 +17,8 @@
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 #
 
+romstage-y += fam15tn_callouts.c
+
 ramstage-y += northbridge.c
+ramstage-y += fam15tn_callouts.c
+