commit 7b21879622a974d4ca92da760be7c7008732b6c3
author Lei YU <mine260309@gmail.com> Thu Feb 09 12:10:13 2017 +0800
committer Lei YU <mine260309@gmail.com> Mon Oct 16 20:40:01 2017 +0800
tree 601a054f428ddcff726fa314064119326f678c34
parent 7f4fca554b250d40230d5735d1d0ddf9ac6af801

Implement HostEpoch set time logic

1. When setting host epoch, follow below logic:

        Mode  | Owner | Set Host Time
        ----- | ----- | -------------
        NTP   | BMC   | Not allowed
        NTP   | HOST  | Not allowed
        NTP   | SPLIT | OK, and just save offset
        NTP   | BOTH  | Not allowed
        MANUAL| BMC   | Not allowed
        MANUAL| HOST  | OK, and set time to BMC
        MANUAL| SPLIT | OK, and just save offset
        MANUAL| BOTH  | OK, and set time to BMC

2. If owner is SPLIT and BMC time is changed, update the offset accordinly;
3. Use timerfd to get notified on BMC time change, and update host time
diff accordingly;
4. Add unit test cases.

Change-Id: I2d60a821f7da9b689c579ae7ab672cc37967322c
Signed-off-by: Lei YU <mine260309@gmail.com>