dt-bindings: Add Marvell PXA1928 USB and HSIC PHY bindings

Add PHY binding for Marvell PXA1928 SOC's USB and HSIC PHYs.
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/phy/pxa1928-usb-phy.txt

+* Marvell PXA1928 USB and HSIC PHYs
+
+Required properties:
+- compatible: "marvell,pxa1928-usb-phy" or "marvell,pxa1928-hsic-phy"
+- reg: base address and length of the registers
+- clocks - A single clock. From common clock binding.
+- #phys-cells: should be 0. From commmon phy binding.
+- resets: reference to the reset controller
+
+Example:
+
+	usbphy: phy@7000 {
+		compatible = "marvell,pxa1928-usb-phy";
+		reg = <0x7000 0xe0>;
+		clocks = <&apmu_clocks PXA1928_CLK_USB>;
+		#phy-cells = <0>;
+	};
+