firmware: arm_scmi: Simplify error path in scmi_dvfs_device_opps_add()

Let's simplify the code in scmi_dvfs_device_opps_add() by using
dev_pm_opp_remove_all_dynamic() in the error path.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20230925131715.138411-8-ulf.hansson@linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>