arm64: dts: rockchip: Fix rk3308 codec@ff560000 reset-names

The commit 30d72458 ("arm64: dts: rockchip: add the internal audio
codec on rk3308") added codec@ff560000 node to SoC DT. However, the
node does not pass DT schema validation:

  codec@ff560000: reset-names:0: 'codec' was expected
        from schema $id: http://devicetree.org/schemas/sound/rockchip,rk3308-codec.yaml#

Use the expected codec reset name to fix this.

Fixes: 30d72458

 ("arm64: dts: rockchip: add the internal audio codec on rk3308")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Link: https://lore.kernel.org/r/20240521211029.1236094-3-jonas@kwiboo.se
Signed-off-by: Heiko Stuebner <heiko@sntech.de>