dt-bindings: display/msm: move DSI PHY bindings to phy/ subdir

Historically DSI PHY bindings landed to the display/msm subdir, however
they describe PHYs and as such they should be in the phy/ subdir.
Follow the example of other Qualcomm display-related PHYs (HDMI, eDP)
and move bindings for the Qualcomm DSI PHYs to the correct subdir.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/709008/
Link: https://lore.kernel.org/r/20260305-msm-dsi-phy-v1-1-0a99ac665995@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Documentation/devicetree/bindings/phy/qcom,dsi-phy-common.yaml

@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/qcom,dsi-phy-common.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Display DSI PHY Common Properties
+
+maintainers:
+  - Krishna Manikandan <quic_mkrishn@quicinc.com>
+
+description:
+  Common properties for Qualcomm Display DSI PHY.
+
+properties:
+  "#clock-cells":
+    const: 1
+    description:
+      See include/dt-bindings/clock/qcom,dsi-phy-28nm.h for clock IDs.
+
+  "#phy-cells":
+    const: 0
+
+  clocks:
+    items:
+      - description: Display AHB clock
+      - description: Board XO source
+
+  clock-names:
+    items:
+      - const: iface
+      - const: ref
+
+required:
+  - clocks
+  - clock-names
+  - "#clock-cells"
+  - "#phy-cells"
+
+additionalProperties: true
+...