firmware: arm_scmi: Clear channel on reception of unexpected responses

When an unexpected response message is received we currently warn the user
and bail-out, ensure to also free the channel by invoking the transport
independent operation .clear_channel()

Link: https://lore.kernel.org/r/20200420152315.21008-3-cristian.marussi@arm.com


Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>