tests: Fix parallel-vm.py test case name parsing

The 'params' argument was not used at all. Use it as an alternative
means for setting the list of test cases to execute.

Signed-off-by: Jouni Malinen <j@w1.fi>
diff --git a/tests/hwsim/vm/parallel-vm.py b/tests/hwsim/vm/parallel-vm.py
index 4622512..ae43fe0 100755
--- a/tests/hwsim/vm/parallel-vm.py
+++ b/tests/hwsim/vm/parallel-vm.py
@@ -357,15 +357,19 @@
         codecov = False
 
     first_run_failures = []
-    tests = []
-    cmd = [ os.path.join(os.path.dirname(scriptsdir), 'run-tests.py'), '-L' ]
-    if args.testmodules:
-        cmd += [ "-f" ]
-        cmd += args.testmodules
-    lst = subprocess.Popen(cmd, stdout=subprocess.PIPE)
-    for l in lst.stdout.readlines():
-        name = l.split(' ')[0]
-        tests.append(name)
+    if args.params:
+        tests = args.params
+    else:
+        tests = []
+        cmd = [ os.path.join(os.path.dirname(scriptsdir), 'run-tests.py'),
+                '-L' ]
+        if args.testmodules:
+            cmd += [ "-f" ]
+            cmd += args.testmodules
+        lst = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+        for l in lst.stdout.readlines():
+            name = l.split(' ')[0]
+            tests.append(name)
     if len(tests) == 0:
         sys.exit("No test cases selected")