Tracing: Incorrect Unlock Mutex Trace Hook Fix

Changed location of the last k_mutex_unlock trace hook since it was
being called after k_sched_unlock, which could result in tracing
scenarios (other thread waiting for lock) where it appeared that a
mutex was being locked again before becoming unlocked.

Signed-off-by: Torbjörn Leksell <torbjorn.leksell@percepio.com>