dt-bindings: mfd: aspeed-lpc: Convert to YAML schema

Convert the bindings of Aspeed LPC from text file into YAML schema.

Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Link: https://lore.kernel.org/r/20210927023053.6728-3-chiawei_wang@aspeedtech.com


[robh: Add 'additionalProperties: false' in child nodes and #reset-cells]
Signed-off-by: Rob Herring <robh@kernel.org>