arm64: dts: renesas: r8a77965: Add Sound and Audio DMAC device nodes

Based on a similar patch of the R8A7796 device tree
by Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Tested-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>