cpuidle: calxeda: add support to use PSCI calls

This updates the Calxeda cpuidle driver to use PSCI calls to powergate
cores. This also enables cpuidle for the ECX-2000.

This could possibly become a generic PSCI driver, but there are no other
PSCI users in the kernel other than mach-virt.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-pm@vger.kernel.org

arch/arm/mach-highbank/highbank.c

@@ -168,7 +168,7 @@ static void __init highbank_init(void)
 
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 
-	if (of_machine_is_compatible("calxeda,highbank"))
+	if (psci_ops.cpu_suspend)
 		platform_device_register(&highbank_cpuidle_device);
 }