[ACPI] Disable EC burst mode w/o disabling EC interrupts

Need to de-couple the concept of polling/interrupts
vs burst/non-burst.

http://bugzilla.kernel.org/show_bug.cgi?id=4980



Signed-off-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>