Unify qnx atomic unit with posix atomic implementation. Jira NVGPU-2125 Change-Id: I64f920b04795f3da5720a9963fb36fc43bf48c4d Signed-off-by: ajesh <akv@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/2084658 Reviewed-by: Automatic_Commit_Validation_User GVS: Gerrit_Virtual_Submit Reviewed-by: Alex Waterman <alexw@nvidia.com>