PCI: dwc/meson: Rework PCI config and DW port logic register accesses

PCI: dwc/meson: Rework PCI config and DW port logic register accesses

The meson 'elbi' registers are just the Designware 'dbi' space and all
the registers accessed are either standard PCI config space or DWC port
logic registers. Convert the accesses to use the common defines and
register accessors.

Link: https://lore.kernel.org/r/20200821035420.380495-28-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Yue Wang <yue.wang@Amlogic.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: linux-amlogic@lists.infradead.org