arm64: dts: zii-ultra: remove second GEN_3V3 regulator instance

When adding the sound support a second instance of the GEN_3V3 regulator was
added by accident. Remove it and point the consumers to the first instance.

Fixes: 663a5b5e

 ("arm64: dts: zii-ultra: add sound support")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>