mb/51nb to mb/gigabyte: Rename Makefiles from .inc to .mk

The .inc suffix is confusing to various tools as it's not specific to
Makefiles. This means that editors don't recognize the files, and don't
open them with highlighting and any other specific editor functionality.

This issue is also seen in the release notes generation script where
Makefiles get renamed before running cloc.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: I422cb475723006ca42be93508fb0bf4b1e4e84d3
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80104
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>
Reviewed-by: Erik van den Bogaert <ebogaert@eltan.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

0 files changed, 0 insertions, 0 deletions