ARM: psci: cpuidle: Enable PSCI CPUidle driver

Allow selection of the PSCI CPUidle in the kernel by updating
the respective Kconfig entry.

Remove PSCI callbacks from ARM/ARM64 generic CPU ops
to prevent the PSCI idle driver from clashing with the generic
ARM CPUidle driver initialization, that relies on CPU ops
to initialize and enter idle states.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will@kernel.org>

drivers/firmware/psci/psci.c

@@ -436,16 +436,6 @@ int psci_cpu_suspend_enter(unsigned long index)
 
 	return ret;
 }
-
-/* ARM specific CPU idle operations */
-#ifdef CONFIG_ARM
-static const struct cpuidle_ops psci_cpuidle_ops __initconst = {
-	.suspend = psci_cpu_suspend_enter,
-	.init = psci_dt_cpu_init_idle,
-};
-
-CPUIDLE_METHOD_OF_DECLARE(psci, "psci", &psci_cpuidle_ops);
-#endif
 #endif
 
 static int psci_system_suspend(unsigned long unused)