Add Maximum and Average history interfaces

These interfaces hold arrays to store the histories
of averages and maximums, along with a timestamp with
each value.

A real world example is using these to expose the 30
second input power averages and maximums that certain
power supplies provide.

Change-Id: I8ea42ae7c334488a1834535ca5256e358fba027d
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
2 files changed