mfd: max77541: Add ADI MAX77541/MAX77540 PMIC Support

MFD driver for MAX77541/MAX77540 to enable its sub devices.

The MAX77541 is a multi-function devices. It includes buck converter and ADC.

The MAX77540 is a high-efficiency buck converter with two 3A switching phases.

They have same regmap except for ADC part of MAX77541.

Signed-off-by: Okan Sahin <okan.sahin@analog.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230412111256.40013-6-okan.sahin@analog.com
Signed-off-by: Lee Jones <lee@kernel.org>