lib/drmtest: Add drmtest_subtest_block macro

Doesn't do more than an if (drmtest_run_test(name)) right now, but
as soon as we get a bit of infrastructure to handle test failures and
skipping, this will get more interesting.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

lib/drmtest.h

@@ -95,6 +95,7 @@ void drmtest_progress(const char *header, uint64_t i, uint64_t total);
 /* subtest infrastructure */
 void drmtest_subtest_init(int argc, char **argv);
 bool drmtest_run_subtest(const char *subtest_name);
+#define drmtest_subtest_block(name) if (drmtest_run_subtest((name)))
 bool drmtest_only_list_subtests(void);
 
 /* helpers to automatically reduce test runtime in simulation */