firmware: arm_scmi: Check for notification support

When registering protocol events, use the optional .is_notify_supported
callback provided by the protocol to check if that specific notification
type is available for that particular resource on the running system,
marking it as unsupported otherwise.

Then, when a notification enable request is received, return an error if
it was previously marked as unsuppported, so avoiding to send a needless
notification enable command and check the returned value for failure.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240212123233.1230090-2-cristian.marussi@arm.com


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