arm64: renesas: salvator-common: sound clock-frequency needs descending order

It will be used ADG clock initial settings, and will be
sound codec's initial system clock which needs maximum clock frequency.
Thus, descending order is required

Fixes: d37d2b3c ("arm64: dts: salvator-x: add 12288000 for sound ADG")
Fixes: 0b03c32d ("arm64: dts: r8a7795: salvator-x: Add support for R-Car H3 ES2.0")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>