Move Archos battery runtime estimation defines into config files instead of powermgmt...

Move Archos battery runtime estimation defines into config files instead of powermgmt.h.  Replace old default values (which were actually the Archos Player currents) with a new default (1mA).  This should give nonsense runtime estimates (instead of semi-reasonable but completely wrong estimates) on all players that do not have a battery current defined.  Hopefully this will remind people that they should define the battery current when they start a new port.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21565 a1c6a512-1295-4272-9138-f99709370657