dt-bindings: mfd: Add documentation for S2MU005 PMIC

dt-bindings: mfd: Add documentation for S2MU005 PMIC

Samsung's S2MU005 PMIC includes subdevices for a charger, an MUIC (Micro
USB Interface Controller), and flash and RGB LED controllers.

Add the compatible and documentation for the S2MU005 PMIC. Also, add an
example for nodes for supported sub-devices, i.e. MUIC, flash LEDs, and
RGB LEDs. Charger sub-device uses the node of the parent.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260516-s2mu005-pmic-v7-3-73f9702fb461@disroot.org
Signed-off-by: Lee Jones <lee@kernel.org>