dt-bindings: phy: qcom,qusb2: Document IPQ5210 compatible

dt-bindings: phy: qcom,qusb2: Document IPQ5210 compatible

Document the QUSB2 PHY compatible for the IPQ5210 SoC. The IPQ5210 PHY is
compatible with the IPQ6018 QUSB2 PHY, so allow it to use
qcom,ipq6018-qusb2-phy as the fallback compatible.

Signed-off-by: Varadarajan Narayanan <varadarajan.narayanan@oss.qualcomm.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260608103344.2740174-2-varadarajan.narayanan@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>