power: supply: Add support for Maxim MAX8971 charger

The MAX8971 is a compact, high-frequency, high-efficiency switch-mode
charger for a one-cell lithium-ion (Li+) battery.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Link: https://lore.kernel.org/r/20250430055114.11469-3-clamor95@gmail.com


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>