pmdomain: arm: scmi_pm_domain: Remove redundant state verification

Currently, scmi_pd_power() explicitly verifies whether the requested
power state was applied by calling state_get(). While this check could
detect failures where the state was not properly updated, ensuring
correctness is the responsibility of the SCMI firmware.

Removing this redundant state_get() call eliminates an unnecessary
round-trip to the firmware, improving efficiency. Any mismatches
between the requested and actual states should be handled by the SCMI
firmware, which must return a failure if state_set() is unsuccessful.

Additionally, in some cases, checking the state after powering off a
domain may be unreliable or unsafe, depending on the firmware
implementation.

This patch removes the redundant verification, simplifying the function
without compromising correctness.

Reported-and-tested-by: Ranjani Vaidyanathan <ranjani.vaidyanathan@nxp.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20250314095851.443979-1-sudeep.holla@arm.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: sudeep-holla

drivers/pmdomain/arm/scmi_pm_domain.c

@@ -24,22 +24,15 @@ struct scmi_pm_domain {
 
 static int scmi_pd_power(struct generic_pm_domain *domain, bool power_on)
 {
-	int ret;
-	u32 state, ret_state;
+	u32 state;
 	struct scmi_pm_domain *pd = to_scmi_pd(domain);
 
 	if (power_on)
 		state = SCMI_POWER_STATE_GENERIC_ON;
 	else
 		state = SCMI_POWER_STATE_GENERIC_OFF;
 
-	ret = power_ops->state_set(pd->ph, pd->domain, state);
-	if (!ret)
-		ret = power_ops->state_get(pd->ph, pd->domain, &ret_state);
-	if (!ret && state != ret_state)
-		return -EIO;
-
-	return ret;
+	return power_ops->state_set(pd->ph, pd->domain, state);
 }
 
 static int scmi_pd_power_on(struct generic_pm_domain *domain)