dt-bindings: arm: mediatek: Drop MT8192 Chromebook variants that never shipped

The Hayato rev5 sku2 and Spherion rev4 variants were designed in
anticipation of shortages of the headphone codec. This never happened.
As far as our records show: the variants were never produced or
shipped, and no such devices were deployed to any lab.

Drop them.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20241224084839.2904335-1-wenst@chromium.org


Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>