amd/common/block/pi: Make agesa_heap_base() static

Convert agesa_heap_base() to static since it's unused outside of
heapmanager.c.

Change-Id: I3ee162985ca1ea36461ea413416d98451a700f8c
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/25457
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
2 files changed