Fix malformed CUDA version macro check

The CUDA_VERSION macro check is incorrect in two places. The first is
harmless as it is related to legacy CUDA 3.2 version's reporting. The
second occurrence affects the check that enables stream priorities and
due to the incorrect check, with CUDA 5.5 priorities have not been used.

Fixes #1594

Change-Id: Icf781d41549c39b6b913c11bb11d4dc4e9f3be9c