riscv: dts: spacemit: Add a PCIe regulator

Define a 3.3v fixed voltage regulator to be used by PCIe on the
Banana Pi BPI-F3.  On this platform, this regulator is always on.

Signed-off-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Tested-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20251218151235.454997-5-elder@riscstar.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>

Author: alexelder

arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts

@@ -33,6 +33,14 @@
 		};
 	};
 
+	pcie_vcc_3v3: pcie-vcc3v3 {
+		compatible = "regulator-fixed";
+		regulator-name = "PCIE_VCC3V3";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-always-on;
+	};
+
 	reg_dc_in: dc-in-12v {
 		compatible = "regulator-fixed";
 		regulator-name = "dc_in_12v";