Number of free masters is not set correctly in stm
free path. Fix this by properly adding the number
of output channels before setting them to 0 in
stm_output_disclaim().

Currently it is equivalent to doing nothing since
master->nr_free is incremented by 0.

Fixes: 7bd1d409 ("stm class: Introduce an abstraction for System Trace Module devices")
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: stable@vger.kernel.org # v4.4
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>