coresight: Remove recursive mutex usage

Call to reset source sink node leads to us trying to take
recursive mutex which results in a deadlock. Move mutex call
to avoid this issue.

Change-Id: Ia1396b08a63fe9d9890c0ef8e6ca5ec4f553b714
Signed-off-by: Satyajit Desai <sadesai@codeaurora.org>