dts: sdm845-db845c: add u-boot fixups

The USB VBUS supply for the type-A port is enabled via a GPIO regulator.
This is incorrectly modelled in Linux where only the PCIe dependency is
expressed. The correct way to handle this will be through a
usb-connector node, but for now we'll just mark the regulator as
always-on so that it will be enabled automatically during boot.

Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/arch/arm/dts/sdm845-db845c-u-boot.dtsi b/arch/arm/dts/sdm845-db845c-u-boot.dtsi
new file mode 100644
index 0000000..906f9fa
--- /dev/null
+++ b/arch/arm/dts/sdm845-db845c-u-boot.dtsi
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Needed for Linux to boot from USB, otherwise if PCIe driver is not in initramfs
+ * the VBUS supply will never get turned on.
+ * https://lore.kernel.org/linux-arm-msm/20240320122515.3243711-1-caleb.connolly@linaro.org/
+ */
+&pcie0_3p3v_dual {
+	regulator-always-on;
+};