PCI: qcom: Add missing supplies required for msm8996

This patch adds supplies that are required for msm8996. vdda
is analog supply that go in to controller, and vddpe_3v3 is
supply to PCIe endpoint.

Without these supplies PCIe endpoints which require power supplies are
not enumerated at all, as there is no one to power it up.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/qcom,pcie.txt

@@ -189,6 +189,10 @@
 	Value type: <phandle>
 	Definition: A phandle to the analog power supply for IC which generates
 		    reference clock
+- vddpe-3v3-supply:
+	Usage: optional
+	Value type: <phandle>
+	Definition: A phandle to the PCIe endpoint power supply
 
 - phys:
 	Usage: required for apq8084