trace: Do not use latency format for ftrace minidump

Minidump ftrace need absolute timestamp of an event, and
not the relative timestamp from buffer start time. So,
do not use latency format for them.

Change-Id: I5ed1aaac62a16e312d8c1d2f3fcbfc2781c4af77
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>