locking/rtmutex: Rename argument in the rt_mutex_adjust_prio_chain() documentation as well

The following commit changed "deadlock_detect" to "chwalk":

   8930ed80 ("rtmutex: Cleanup deadlock detector debug logic")

do that rename in the function's documentation as well.

Signed-off-by: Tom(JeHyeon) Yeon <tom.yeon@windriver.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1426655010-31651-1-git-send-email-tom.yeon@windriver.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>