ACPI / EC: Restore polling during noirq suspend/resume phases

Commit 66259146 (ACPI / EC: Drop EC noirq hooks to fix a
regression) modified the ACPI EC driver so that it doesn't switch
over to busy polling mode during noirq stages of system suspend and
resume in an attempt to fix an issue resulting from that behavior.

However, that modification introduced a system resume regression on
Thinkpad X240, so make the EC driver switch over to the polling mode
during noirq stages of system suspend and resume again, which
effectively reverts the problematic commit.

Fixes: 66259146

 (ACPI / EC: Drop EC noirq hooks to fix a regression)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197863
Reported-by: Markus Demleitner <m@tfiu.de>
Tested-by: Markus Demleitner <m@tfiu.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>