ACPI: EC: Add wait for irq storm

Merge of poll and irq modes accelerated EC transaction, so
that keyboard starts to suffer again. Add msleep(1) into
transaction path for the storm to allow keyboard controller
to do its job.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=14747

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --cc drivers/acpi/ec.c
Simple merge