Revert "ACPI: battery: Convert discharge energy rate to current properly"

This reverts commit 558073dd56707864f09d563b64e7c37c021e89d2, along with
the failed try to fix the regression it caused ("ACPI: Fix ACPI battery
regression introduced by commit 558073"), which just made things worse.

Commit aaad077638be1a25871bcae5e43952d6b63abfca (that failed "Fix ACPI
battery regression") got the voltage conversion confused, and fixed the
problem with Rafael's battery monitor apparently just by mistake.

So revert them both, getting us back to the 2.6.27 state in this, and
let's revisit it when people understand what's going on.

Noted-by: Paul Martin <pm@debian.org>
Requested-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <len.brown@intel.com>
Cc: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>