logcat: liblog: Add "usec" format argument

(cherry pick from commit e1f2004ecc05ce2d5d4313d16c7791594643f2ef)

- Add additional 3 digits of time precision for time output
  adding in the reporting of usec
- Remove trailing space in header file

Change-Id: Ifb560850b8e01080e126fbaeab640db71cce3eea
3 files changed