both arches don't support push anything to stack except registers

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com

Bug: 
Change-Id: I5682fc1634bc66c8aa28889abe5b977092b004f6
Reviewed-on: https://chromium-review.googlesource.com/598644Reviewed-by: Jaideep Bajwa <bjaideep@ca.ibm.com>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#47096}