PM / s2idle: Rename ->enter_freeze to ->enter_s2idle

Rename the ->enter_freeze cpuidle driver callback to ->enter_s2idle
to make it clear that it is used for entering suspend-to-idle and
rename the related functions, variables and so on accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c
index ae8eb03..5ba9fab 100644
--- a/drivers/cpuidle/dt_idle_states.c
+++ b/drivers/cpuidle/dt_idle_states.c
@@ -41,9 +41,9 @@ static int init_state_node(struct cpuidle_state *idle_state,
 	/*
 	 * Since this is not a "coupled" state, it's safe to assume interrupts
 	 * won't be enabled when it exits allowing the tick to be frozen
-	 * safely. So enter() can be also enter_freeze() callback.
+	 * safely. So enter() can be also enter_s2idle() callback.
 	 */
-	idle_state->enter_freeze = match_id->data;
+	idle_state->enter_s2idle = match_id->data;
 
 	err = of_property_read_u32(state_node, "wakeup-latency-us",
 				   &idle_state->exit_latency);