monitor: Support a separate upper deviation

Add an optional 'upper_deviation' field to the fan monitor config and if
supplied it will be used for the allowed deviation when the fan value is
over the target.  If not supplied it will work as today and the single
deviation value will be used for both the upper and lower bounds.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I085dc1996832e79b94bd1df3a05681d107f466eb
8 files changed