sh: hp6xx: Correct APM output.

This patch fixes the old non-verbose hp6xx apm code and enables some
very basic apm output.  We now get percentage (battery) output
and basic time estimate.

Signed-off-by: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>