[Artful Patch] ltp rwtest - Unable to handle kernel paging request at virtual address

[Manoj Iyer]

Please consider this patch to Artful that fixes bug: 
https://launchpad.net/bugs/1721067. The patch was cherry-picked cleanly from
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git. 

This patch was tested by me on a QDF2400 system and test results are posted
to the bug report. The patch touches ARM64 code and does not impact any other
architecture. 

Thanks
Manoj Iyer