DO NOT MERGE ANYWHERE Fix the timestamp in btsnoop format

Due to overflow, timestamp does not have correct value.
Make sure it should be saved in long long type as 64bit.

Change-Id: Iaf1b1dd746dd52ab7e50b870efacde2b8dd0bed6
Signed-off-by: Ben YoungTae Kim <ytkim@qca.qualcomm.com>