dt-bindings: PCI: tegra194: Fix PCIe endpoint node names

As defined by Documentation/devicetree/bindings/pci/pci-ep.yaml,
PCIe endpoints match this pattern:

	properties:
	  $nodename:
	    pattern: "^pcie-ep@"

Change the existing ones in the DT bindings examples to avoid warnings
during DT bindings validation.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>