regulator: dt-bindings: mt6315: Document MT6319 PMIC

regulator: dt-bindings: mt6315: Document MT6319 PMIC

The MT6319 is a pin-compatible drop-in replacement for MT6315 with
slightly better electrical characteristics.

It's unclear whether there are any differences, since the downstream
implementation doesn't describe the MT6319 separately. Neither does the
implementation check chip IDs, even though those are available.

Add a new compatible for the MT6319 just in case differences are
discovered later and fall back to the MT6315 compatible.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20240620094746.2404753-2-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>