mb/gigabyte/ga-945gcm-s2c: Add mainboard using variants

This mainboard is identical to ga-945gcm-s2l except for NIC
which is a Realtek RTL 8101E chip (10/100 Mbit).

The schematics of ga-945gcm-s2l mention multiple NICs and ga-945gcm-s2c
and ga-945gcm-s2l have a common manual further indicating that those
boards are close to identical.

Change-Id: Iba3d401efcf208154e639c3237b201830a5151aa
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/17416
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
4 files changed