ARM: dts: imx6ull: update vdd_soc voltage for 900MHz operating point

Update VDD_SOC voltage to 1.25V for 900MHz operating point
according to datasheet Rev. 1.3, 08/2018, 25mV is added to
the minimum allowed values to cover power supply ripple.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6ull.dtsi

@@ -22,7 +22,7 @@ &cpu0 {
 	>;
 	fsl,soc-operating-points = <
 		/* KHz	uV */
-		900000	1175000
+		900000	1250000
 		792000	1175000
 		528000	1175000
 		396000	1175000