mb/gigabyte/ga-h61m-series: Add GA-H61M-DS2

mb/gigabyte/ga-h61m-series: Add GA-H61M-DS2

Built from a mixture of autoport output, other variants, schematics and
expert guesswork. I don't have this board, but the code has been tested
by someone else and boots successfully (first try) with TianoCore. It's
reasonable to assume most things work, as this board is very similar to
the already-supported variants.

Change-Id: I3d8df483e5573f77782b7d18b1410b391bfe387d
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61541
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>