gdb/testsuite: add linux target check in allow_hipcc_tests

ROCm / HIP tests should only run on Linux for now, existing gdb.rocm
tests miss such a check.  Add an "istarget linux" check in
allow_hipcc_tests.

Change-Id: I71f69e510a754f2fdadc32de53b923ebb9835ab5
Approved-By: Lancelot Six <lancelot.six@amd.com>
1 file changed