firmware: arm_scmi: Improve checks in the info_get operations

firmware: arm_scmi: Improve checks in the info_get operations

SCMI protocols abstract and expose a number of protocol specific
resources like clocks, sensors and so on. Information about such
specific domain resources are generally exposed via an `info_get`
protocol operation.

Improve the sanity check on these operations where needed.

Link: https://lore.kernel.org/r/20220817172731.1185305-3-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>