sensor-cache: Initial commit

This is the initial commit of a series of changes for caching the
sensors in ipmid, so that the ipmi sensor/sdr related handlers could use
the cached values instead of getting the sensors from DBus.

The goal is to improve the ipmi sensor list's performance.
With all the patches in the series, the ipmitool sensor list time on
g220a (140+ sensors) is reduced from 20s+ to about 11s.

Tested: Manually verify the matches are working correctly in QEMU.

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: I4c4be8613dd89b5a83d8ff59354a8a3991e98cbf
1 file changed