ARM: dts: microchip: at91-sama7g54_curiosity: Replace regulator-suspend-voltage with the valid property

By checking the pmic node with microchip,mcp16502.yaml#
'regulator-suspend-voltage' does not match any of the
regexes 'pinctrl-[0-9]+' from schema microchip,mcp16502.yaml#
which inherits regulator.yaml#. So replace regulator-suspend-voltage
with regulator-suspend-microvolt to avoid the inconsitency.

Fixes: ebd6591f8ddb ("ARM: dts: microchip: sama7g54_curiosity: Add initial device tree of the board")
Signed-off-by: Andrei Simion <[e-mail]>
Acked-by: Nicolas Ferre <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Claudiu Beznea <[e-mail]>

arch/arm/boot/dts/microchip/at91-sama7g54_curiosity.dts

···
 
 					regulator-state-standby {
 						regulator-on-in-suspend;
-						regulator-suspend-voltage = <1150000>;
+						regulator-suspend-microvolt = <1150000>;
 						regulator-mode = <4>;
 					};
 
···
 
 					regulator-state-standby {
 						regulator-on-in-suspend;
-						regulator-suspend-voltage = <1050000>;
+						regulator-suspend-microvolt = <1050000>;
 						regulator-mode = <4>;
 					};
 
···
 					regulator-always-on;
 
 					regulator-state-standby {
-						regulator-suspend-voltage = <1800000>;
+						regulator-suspend-microvolt = <1800000>;
 						regulator-on-in-suspend;
 					};
 
···
 					regulator-always-on;
 
 					regulator-state-standby {
-						regulator-suspend-voltage = <3300000>;
+						regulator-suspend-microvolt = <3300000>;
 						regulator-on-in-suspend;
 					};