[ACPI] Enable EC Burst Mode

Fixes several Embedded Controller issues, including
button failure and battery status AE_TIME failure.

http://bugzilla.kernel.org/show_bug.cgi?id=3851

Based on patch by: Andi Kleen <ak@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>