systemc: Always set USE_SYSTEMC=1 when compiling with verify.py.

It doesn't make sense not to have systemc enabled when building the
systemc regression tests.

Change-Id: I23b81fd4d7cbd0dbf5efbea773d816296d6492be
Reviewed-on: https://gem5-review.googlesource.com/12065
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/tests/verify.py

@@ -121,7 +121,7 @@ class CompilePhase(TestPhaseBase):
 
     def run(self, tests):
         targets = list([test.full_path() for test in tests])
-        scons_args = list(self.args) + targets
+        scons_args = [ 'USE_SYSTEMC=1' ] + list(self.args) + targets
         scons(*scons_args)
 
 class RunPhase(TestPhaseBase):