ASoC: rsnd: Add RZ/G3E audio driver support

John Madieu <john.madieu.xa@bp.renesas.com> says:

Add audio support for the Renesas RZ/G3E SoC to the R-Car Sound
driver. The RZ/G3E audio subsystem is based on R-Car Sound IP but
has several differences requiring dedicated handling:

  - SSI operates exclusively in BUSIF mode (no PIO)
  - 2-4 BUSIF channels per SSI (layout differs from R-Car)
  - Separate register regions for SCU, ADG, SSIU, SSI accessed by name
  - Per-SSI ADG and SSIF supply clocks
  - Dedicated audmapp clock/reset for Audio DMAC peri-peri
  - Per-SSI and per-module reset controllers via CPG
  - Unprefixed DT sub-node names (ssi, ssiu, src, ...) instead of
    rcar_sound,xxx
  - Hyphenated indexed clock/reset names (ssi-0, src-0, adg-ssi-0,
    audio-clka, ...) instead of the legacy dotted form

Link: https://patch.msgid.link/20260525110230.4014435-1-john.madieu.xa@bp.renesas.com