arm64: dts: meson: odroid-n2 plus: fix vddcpu_a pwm

On the odroid N2 plus, cpufreq is not available due to an error on the cpu
regulators. vddcpu a and b get the same PWM. The one provided to vddcpu A
is incorrect. Because vddcpu B PWM is busy the regulator cannot register:

> pwm-regulator regulator-vddcpu-b: Failed to get PWM: -16

Like on the odroid n2, use PWM A out of GPIOE_2 for vddcpu A to fix the
problem

Fixes: 98d24896 ("arm64: dts: meson: add support for the ODROID-N2+")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20201023094139.809379-1-jbrunet@baylibre.com

arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2-plus.dts

@@ -19,7 +19,7 @@ &vddcpu_a {
 	regulator-min-microvolt = <680000>;
 	regulator-max-microvolt = <1040000>;
 
-	pwms = <&pwm_AO_cd 1 1500 0>;
+	pwms = <&pwm_ab 0 1500 0>;
 };
 
 &vddcpu_b {