ASoC: rsnd: adg: Look up RZ/G3E clkin under audio-clk{a,b,c,i}

ASoC: rsnd: adg: Look up RZ/G3E clkin under audio-clk{a,b,c,i}

The R-Car Sound ADG block has up to four external master-clock inputs
named CLKA, CLKB, CLKC and CLKI by the silicon. On Gen2 R-Car these
come from DT under the legacy names "clk_a", "clk_b", "clk_c", "clk_i"
defined by renesas,rsnd.yaml. Gen4 collapses them to a single "clkin".

The new standalone RZ/G3E sound binding (renesas,r9a09g047-sound.yaml)
uses the standard DT naming convention with a vendor-meaningful prefix
that matches the SoC datasheet pin labels: "audio-clka", "audio-clkb",
"audio-clkc", "audio-clki".

Add a third clkin name table for RZ/G3E and dispatch to it from
rsnd_adg_get_clkin() in the same style as the existing Gen4 branch.
The CLKA/B/C/I enum values, the clkin[] array, and the BRGA/BRGB
derivation are unchanged - only the DT lookup names differ.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://patch.msgid.link/20260525110230.4014435-15-john.madieu.xa@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>