coresight: add header meta data for every ost packet sent via stm

Add header meta data carrying useful info like version, magic,
task name, cpu and kernel timestamp with every OST packet sent
using STM.

This will help provide additional info that can be used for STM
log analysis.

Change-Id: I8902f5529d62417ee8b4d6a21f3801c06edce972
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>