dt-bindings: mfd: rk808: Convert bindings to yaml

Convert the rk808 bindings into yaml format. clock-output-names varies
in maxItems depending on whether or not the clock-cells is 0 or 1. For
the rk805, rk809, and rk817. This preserves behavior with the existing
driver handling setting the clock for these specific PMICs. When this
driver is corrected and the devicetrees updated this logic can be
removed (since the rk805, rk808, and rk817 only have one actual clock).

Note this patch was previously sent as a series, all of the patches in
the series except this one have been committed to mainline.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220519161731.1168-1-macroalpha82@gmail.com