power: supply: Add bd718(15/28/78) charger driver

power: supply: Add bd718(15/28/78) charger driver

Add charger driver for ROHM BD718(15/28/78) PMIC charger block.
It is a stripped down version of the driver here:
https://lore.kernel.org/lkml/dbd97c1b0d715aa35a8b4d79741e433d97c562aa.1637061794.git.matti.vaittinen@fi.rohmeurope.com/

For the ease of review and to do a step-by-step approach remove all the
coloumb counter related stuff and do not sneak in BD71827 support. That
also avoids non-trivial rebasing of the above series.

Changes besides that:
Replace the custom property by a standard one and do not use megaohms
for the current sense resistor.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://patch.msgid.link/20250918-bd71828-charger-v5-2-851164839c28@kemnade.info
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>