dt-bindings: reset: pdc: Convert PDC Global bindings to yaml

Convert PDC Global bindings to yaml and add SC7180 PDC global to the list
of possible bindings.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>