arm64: dts: rockchip: fix num-channels property of wolfvision pf5 mic

arm64: dts: rockchip: fix num-channels property of wolfvision pf5 mic

The Rockchip RK3568 PDM block always considers stereo inputs. Therefore,
the number of channels must be always an even number, even if a single
mono microphone is attached.

Fixes: 0be29f76633a ("arm64: dts: rockchip: add wolfvision pf5 mainboard")
Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Link: https://lore.kernel.org/r/20241218-b4-wolfvision-pf5-update-v1-1-1d1959858708@wolfvision.net
Signed-off-by: Heiko Stuebner <heiko@sntech.de>