Port d3a4d15f

Original Commit Message:

    This reloc mode is never encoded, so there is no reason to
    differentiate between 32 and 64 bit.
    Both are now replaced by RelocInfo::NONE.

R=clemensh@chromium.org, joransiu@ca.ibm.com, bjaideep@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I9a5369315cc2c966bffd3862d15f29aea08960e4
Reviewed-on: https://chromium-review.googlesource.com/881463Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#50815}