arm64: dts: meson-g12a: Fix the pwm regulator supply properties

arm64: dts: meson-g12a: Fix the pwm regulator supply properties

After enabling CONFIG_REGULATOR_DEBUG=y we observe below debug logs.
Changes help link VDDCPU pwm regulator to 12V regulator supply
instead of dummy regulator.

[   11.602281] pwm-regulator regulator-vddcpu: Looking up pwm-supply property
               in node /regulator-vddcpu failed
[   11.602344] VDDCPU: supplied by regulator-dummy
[   11.602365] regulator-dummy: could not add device link regulator.11: -ENOENT
[   11.602548] VDDCPU: 721 <--> 1022 mV at 1022 mV, enabled

Fixes: e9bc0765cc12 ("arm64: dts: meson-g12a: enable DVFS on G12A boards")
Cc: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20210919202918.3556-2-linux.amoon@gmail.com