arm64: dts: renesas: r8a7795: remove BUSIF0 settings from rcar_sound,ssi

arm64: dts: renesas: r8a7795: remove BUSIF0 settings from rcar_sound,ssi

Before, BUSIF which is needed for DMA transfer was automatically handled
via SSI, but it cared BUSIF0 only.
Now, rsnd driver can handle BUSIF0-7 (= for Gen3) BUSIF0-3 (= for Gen2)
via SSIU, and it is keeping compatibility.
Thus, BUSIF0 settings via SSI had been kept to avoid git merge timing
issue / git bisect issue, but it is no longer needed.
This patch removes it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>