arm64: ptrace: add is_wide_instruction() macro

Add the is_wide_instruction() macro. This was copied from the arm
architecture.

Change-Id: I28f83b47f5c587fe778dc2846df77673f8dd918b
Signed-off-by: Alex Van Brunt <avanbrunt@nvidia.com>
Reviewed-on: http://git-master/r/361737


Reviewed-by: Peng Du <pdu@nvidia.com>
Reviewed-on: http://git-master/r/365060


Reviewed-by: Richard Wiley <rwiley@nvidia.com>
Tested-by: Oskari Jaaskelainen <oskarij@nvidia.com>
Git-commit: 0104975c46f6d41a7205b5954bbcb4c25ef8bc6d
Git-repo: https://android.googlesource.com/kernel/tegra


Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>