MIPS: ath79: add lots of missing registers

This patch adds many new registers for various QCA MIPS SoCs. The patch is
an aggragate of many contributions made to OpenWrt.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Henryk Heisig <hyniu@o2.pl>
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Weijie Gao <hackpascal@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Julien Dusser <julien.dusser@free.fr>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19910/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org