mfd: sprd-sc27xx: Switch to devm_mfd_add_devices()

mfd: sprd-sc27xx: Switch to devm_mfd_add_devices()

To allow instantiating subdevices such as the regulator and poweroff
devices that do not have corresponding device tree nodes with a
"compatible" property, use devm_mfd_add_devices() with MFD cells instead
of devm_of_platform_populate(). Since different PMICs in the SC27xx
series contain different components, use separate MFD cell tables for
each PMIC model. Define cells for all components that have upstream
drivers at this point.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
Link: https://patch.msgid.link/20260329-sc27xx-mfd-cells-v3-3-9158dee41f74@abscue.de
Signed-off-by: Lee Jones <lee@kernel.org>