dt-bindings: PCI: dwc: Add clocks/resets common properties

DW PCIe RP/EP reference manuals explicit define all the clocks and reset
requirements in [1] and [2]. Seeing the DW PCIe vendor-specific
DT-bindings have already started assigning random names to the same set of
the clocks and resets lines, let's define a generic names sets and add
them to the DW PCIe common DT-schema.

Note since there are DW PCI-based vendor-specific DT-bindings with the
custom names assigned to the same clocks and resets resources we have no
much choice but to add them to the generic DT-schemas in order to have the
schemas being applicable for such devices. These names are marked as
vendor-specific and should be avoided being used in new bindings in favor
of the generic names.

[1] Synopsys DesignWare Cores PCI Express Controller Databook - DWC PCIe
Root Port, Version 5.40a, March 2019, p.55 - 78.
[2] Synopsys DesignWare Cores PCI Express Controller Databook - DWC PCIe
Endpoint, Version 5.40a, March 2019, p.58 - 81.

Link: https://lore.kernel.org/r/20221113191301.5526-12-Sergey.Semin@baikalelectronics.ru


Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>