ACPI: Revert "ACPI / Battery: Remove battery's proc directory"

ACPI: Revert "ACPI / Battery: Remove battery's proc directory"

commit 3a670cc79342c36d308decd5f90351830ed1685c upstream.

The commit 1e2d9cd and 7d7ee95 remove ACPI Proc Battery
directory and breaks some old userspace tools. This patch
is to revert commit 1e2d9cd.

Fixes: 1e2d9cdfb449 (ACPI / Battery: Remove battery's proc directory)
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>