ARM: imx6qdl-sabresd: set swbst_reg as vbus's parent reg

USB vbus 5V is from PMIC SWBST, so set swbst_reg as vbus's
parent reg, it fixed a bug that the voltage of vbus is incorrect
due to swbst_reg is disabled after boots up.

Cc: [e-mail]
Signed-off-by: Peter Chen <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx6qdl-sabresd.dtsi

···
 			regulator-max-microvolt = <5000000>;
 			gpio = <&gpio3 22 0>;
 			enable-active-high;
+			vin-supply = <&swbst_reg>;
 		};
 
 		reg_usb_h1_vbus: regulator@1 {
···
 			regulator-max-microvolt = <5000000>;
 			gpio = <&gpio1 29 0>;
 			enable-active-high;
+			vin-supply = <&swbst_reg>;
 		};
 
 		reg_audio: regulator@2 {