This patch adds mt8195 dsp document. The dsp is used for Sound Open
Firmware driver node. It includes registers,  clocks, memory regions,
and mailbox for dsp.
Signed-off-by: yc.hung <yc.hung@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220106064847.15588-1-yc.hung@mediatek.comSigned-off-by: Mark Brown <broonie@kernel.org>