Revert "ACPI / EC: Add query flushing support"

Revert commit f252cb09 (ACPI / EC: Add query flushing support),
because it breaks system suspend on Acer Aspire S5.  The machine
just hangs solid at the last stage of suspend (after taking non-boot
CPUs offline).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>