firmware: arm_scmi: Reject SCMI drivers when configured in raw mode

Reject SCMI driver registration when SCMI raw mode support is configured,
so as to avoid interferences between the SCMI raw mode transactions and the
normal SCMI stack operations.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230118121426.492864-15-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>