intel_idle: Fix a cast to pointer from integer of different size warning in intel_idle

Fix the following warning:

drivers/idle/intel_idle.c: In function 'intel_idle_cpuidle_devices_init':
drivers/idle/intel_idle.c:518:5: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

By making get_driver_data() return a long instead of an int.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/idle/intel_idle.c

@@ -197,7 +197,7 @@ static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = {
 		.enter = &intel_idle },
 };
 
-static int get_driver_data(int cstate)
+static long get_driver_data(int cstate)
 {
 	int driver_data;
 	switch (cstate) {