dt-bindings: phy: drop obsolete qcom,usb-8x16-phy bindings

Remove the bindings for the Qualcomm 8x16 PHY driver that was dropped
in commit 4756f35f ("usb: phy: remove phy-qcom-8x16-usb.c") in 2017.
Signed-off-by: Rayyan Ansari <rayyan.ansari@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20240711122016.41806-1-rayyan.ansari@linaro.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/qcom,usb-8x16-phy.txt

-Qualcomm's APQ8016/MSM8916 USB transceiver controller
-
-- compatible:
-    Usage: required
-    Value type: <string>
-    Definition: Should contain "qcom,usb-8x16-phy".
-
-- reg:
-    Usage: required
-    Value type: <prop-encoded-array>
-    Definition: USB PHY base address and length of the register map
-
-- clocks:
-    Usage: required
-    Value type: <prop-encoded-array>
-    Definition: See clock-bindings.txt section "consumers". List of
-                two clock specifiers for interface and core controller
-                clocks.
-
-- clock-names:
-    Usage: required
-    Value type: <string>
-    Definition: Must contain "iface" and "core" strings.
-
-- vddcx-supply:
-    Usage: required
-    Value type: <phandle>
-    Definition: phandle to the regulator VDCCX supply node.
-
-- v1p8-supply:
-    Usage: required
-    Value type: <phandle>
-    Definition: phandle to the regulator 1.8V supply node.
-
-- v3p3-supply:
-    Usage: required
-    Value type: <phandle>
-    Definition: phandle to the regulator 3.3V supply node.
-
-- resets:
-    Usage: required
-    Value type: <prop-encoded-array>
-    Definition: See reset.txt section "consumers". PHY reset specifier.
-
-- reset-names:
-    Usage: required
-    Value type: <string>
-    Definition: Must contain "phy" string.
-
-- switch-gpio:
-    Usage: optional
-    Value type: <prop-encoded-array>
-    Definition: Some boards are using Dual SPDT USB Switch, witch is
-                controlled by GPIO to de/multiplex D+/D- USB lines
-                between connectors.
-
-Example:
-	usb_phy: phy@78d9000 {
-		compatible = "qcom,usb-8x16-phy";
-		reg = <0x78d9000 0x400>;
-
-		vddcx-supply = <&pm8916_s1_corner>;
-		v1p8-supply = <&pm8916_l7>;
-		v3p3-supply = <&pm8916_l13>;
-
-		clocks = <&gcc GCC_USB_HS_AHB_CLK>,
-			     <&gcc GCC_USB_HS_SYSTEM_CLK>;
-		clock-names = "iface", "core";
-
-		resets = <&gcc GCC_USB2A_PHY_BCR>;
-		reset-names = "phy";
-
-		// D+/D- lines: 1 - Routed to HUB, 0 - Device connector
-		switch-gpio = <&pm8916_gpios 4 GPIO_ACTIVE_HIGH>;
-	};
-