arm64: dts: librem5: Limit the USB to 5V

The charge controller can handle 14V but the PTC on the devkit can only
handle 6V so limit the negotiated voltage to 5V.
Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-librem5-devkit.dts

@@ -353,7 +353,7 @@ PDO_FIXED_DUAL_ROLE |
 			sink-pdos = <PDO_FIXED(5000, 2000, PDO_FIXED_USB_COMM |
 				PDO_FIXED_DUAL_ROLE |
 				PDO_FIXED_DATA_SWAP )
-			     PDO_VAR(5000, 12000, 2000)>;
+			     PDO_VAR(5000, 3000, 3000)>;
 			op-sink-microwatt = <10000000>;
 
 			ports {