tracing: Fix lock inversion in trace_event_enable_tgid_record()

       Task T2                             Task T3
trace_options_core_write()            subsystem_open()

 mutex_lock(trace_types_lock)           mutex_lock(event_mutex)

 set_tracer_flag()

   trace_event_enable_tgid_record()       mutex_lock(trace_types_lock)

    mutex_lock(event_mutex)

This gives a circular dependency deadlock between trace_types_lock and
event_mutex. To fix this invert the usage of trace_types_lock and
event_mutex in trace_options_core_write(). This keeps the sequence of
lock usage consistent.

Change-Id: Ide261e25fb15f79391a6220eef246e274b0c6a69
Signed-off-by: Prateek Sood <prsood@codeaurora.org>