arm64: mm: remap dma contiguous memory as non executable

arm64: mm: remap dma contiguous memory as non executable

Dma buffers shouldn't have executable code. To ensure the security,
Map dma contiguous memory as non executable in kernel.

Bug 1859649

Change-Id: I8b4b6d574477f560e9a43b07287014ed981092d3
Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
Reviewed-on: http://git-master/r/1301854
(cherry picked from commit e910098f1d91ce82c18de8b5986be0856e5bc942)
Reviewed-on: http://git-master/r/1497681
Reviewed-by: Kamal Balagopalan <kbalagopalan@nvidia.com>
Tested-by: Kamal Balagopalan <kbalagopalan@nvidia.com>
GVS: Gerrit_Virtual_Submit