PM: EM: use kfree_rcu() to simplify the code

The callback function of call_rcu() just calls kfree(), so use
kfree_rcu() instead of call_rcu() + callback function.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/20250218082021.2766-1-lirongqing@baidu.com


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>