dt-bindings: PCI: tegra: Add sideband pins configuration entries

Add optional bindings "pinctrl-names" and "pinctrl-0" to describe pin
configuration information of a particular PCIe controller.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie.txt

@@ -83,6 +83,11 @@ Required properties:
 - vddio-pex-ctl-supply: Regulator supply for PCIe side band signals
 
 Optional properties:
+- pinctrl-names: A list of pinctrl state names.
+  It is mandatory for C5 controller and optional for other controllers.
+  - "default": Configures PCIe I/O for proper operation.
+- pinctrl-0: phandle for the 'default' state of pin configuration.
+  It is mandatory for C5 controller and optional for other controllers.
 - supports-clkreq: Refer to Documentation/devicetree/bindings/pci/pci.txt
 - nvidia,update-fc-fixup: This is a boolean property and needs to be present to
     improve performance when a platform is designed in such a way that it
@@ -120,6 +125,9 @@ Tegra194:
 		num-lanes = <8>;
 		linux,pci-domain = <0>;
 
+		pinctrl-names = "default";
+		pinctrl-0 = <&pex_rst_c5_out_state>, <&clkreq_c5_bi_dir_state>;
+
 		clocks = <&bpmp TEGRA194_CLK_PEX0_CORE_0>;
 		clock-names = "core";