PM: wakeup: Remove needless return in three void APIs

Remove needless 'return' in the following void APIs:

 __pm_wakeup_event()
 pm_wakeup_event()
 pm_wakeup_hard_event()

Since both the API and callee involved are void functions.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://patch.msgid.link/20250221-rmv_return-v1-14-cc8dff275827@quicinc.com


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