ARM: dts: socfpga: arria10: align regulator node with dtschema

Fixes dtbs_check warnings like:

'3-3-v-regulator' does not match any of the regexes: '.*-names$'

Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

arch/arm/boot/dts/socfpga_arria5_socdk.dts

@@ -50,7 +50,7 @@
 		};
 	};
 
-	regulator_3_3v: 3-3-v-regulator {
+	regulator {
 		compatible = "regulator-fixed";
 		regulator-name = "3.3V";
 		regulator-min-microvolt = <3300000>;