ARM: dts: imx7d-sdb: Set VLDO4 outpt to 2.8V for MIPI CSI/DSI

According to mx7sabresd schematics the MIPI CSI/DSI voltage rails
should be 2.8V but the voltage provided is a maximum of 3.3V and
minimum of 1.8V. Providing such a higher voltage might damage the
peripherals and violates the schematic settings.
Signed-off-by: NGautam Bhat <mindentropy@gmail.com>
Reviewed-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx7d-sdb.dts

@@ -285,8 +285,8 @@
 			};
 
 			vgen6_reg: vldo4 {
-				regulator-min-microvolt = <1800000>;
-				regulator-max-microvolt = <3300000>;
+				regulator-min-microvolt = <2800000>;
+				regulator-max-microvolt = <2800000>;
 				regulator-always-on;
 			};
 		};