arm64: renesas: salvator-common: avoid audio_clkout naming conflict

clock name of "audio_clkout" is used by Renesas sound driver.
This duplicated naming breaks its clock registering/unregistering.
Especially, when unbind/bind it can't handle clkout correctly.
This patch renames "audio_clkout" to "audio-clkout" to avoid
naming conflict.

Fixes: 8a8f181d ("arm64: renesas: salvator-x: use CS2000 as AUDIO_CLK_B")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>