mfd: Add new driver for MAX77705 PMIC

Add the core MFD driver for max77705 PMIC. Drivers for sub-devices
will be added in subsequent patches.

Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250123-starqltechn_integration_upstream-v17-5-8b06685b6612@gmail.com


Signed-off-by: Lee Jones <lee@kernel.org>