pmdomain: arm: Avoid polling for scmi_perf_domain

It was a mistake to prefer polling based mode when setting a performance
level for a domain. Let's instead rely on the protocol to decide what is
best and thus avoid polling when possible.

Reported-by: Nikunj Kela <nkela@quicinc.com>
Fixes: 2af23ceb

 ("pmdomain: arm: Add the SCMI performance domain")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20231127135033.136442-1-ulf.hansson@linaro.org