MIPS: ingenic: Initial GCW Zero support

MIPS: ingenic: Initial GCW Zero support

The GCW Zero (http://www.gcw-zero.com) is a retro-gaming focused
handheld game console, successfully kickstarted in ~2012, running Linux.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Mathieu Malaterre <malat@debian.org>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Maarten ter Huurne <maarten@treewalker.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18490/
Signed-off-by: James Hogan <jhogan@kernel.org>