firmware: arm_scmi: Update doc style comments

Fix minor formatting issues with the doc style comments.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/1bff7c0d1ad2c8b6eeff9660421f414f8c612eb2.1580448239.git.viresh.kumar@linaro.org


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