firmware: arm_scmi: Fix ARCH_COLD_RESET

The defination for ARCH_COLD_RESET is wrong. Let us fix it according to
the SCMI specification.

Link: https://lore.kernel.org/r/20201008143722.21888-5-etienne.carriere@linaro.org


Fixes: 95a15d80 ("firmware: arm_scmi: Add RESET protocol in SCMI v2.0")
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>