intel i945 gm45 x4x: Apply cbmem_top() alignment

Force modest 4 MiB alignment to help with MTRR assignment.

Change-Id: I49a7d1288bc079da1b8bd52150ddcfcfe2e51179
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17780
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
3 files changed