MAINTAINERS: Update SCMI entry with HWMON driver

scmi-hwmon.c is tightly coupled with the SCMI subsystem, fold it under
the SCMI subsystem MAINTAINERS umbrella.

Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20240222193027.920006-1-florian.fainelli@broadcom.com


Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>