qcacmn: Change time format and default configuration in DPTRACE

Fix below in DPTRACE feature:
1) Change timestamp in DPTRACE records to hr:mm:sec.usec format.
2) Change default configuration in qdf_dp_trace_clear_buffer()
   to match that of qdf_dp_trace_init().

Change-Id: Ibad674e3b94a2c7ac5cbefa5fc18efb48f6ca694
CRs-Fixed: 1098928
2 files changed