Now that DWC drivers can setup their own pci_ops for the root and child
buses, convert the Tegra driver to use the standard pci_ops for root
bus config accesses.

Link: https://lore.kernel.org/r/20200821035420.380495-8-robh@kernel.orgSigned-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org