Add I915_EXEC_DEFAULT to list of known engines

I dropped this from the list of rings for some tests when refactoring to
a common array. Almost all of the tests should be run over the default
exec engine to ensure ABI backwards compatiblity.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

lib/igt_gt.c

@@ -539,6 +539,7 @@ unsigned intel_detect_and_clear_missed_interrupts(int fd)
 }
 
 const struct intel_execution_engine intel_execution_engines[] = {
+	{ "default", 0, 0 },
 	{ "render", I915_EXEC_RENDER, 0 },
 	{ "bsd", I915_EXEC_BSD, 0 },
 	{ "bsd1", I915_EXEC_BSD, 1<<13 /*I915_EXEC_BSD_RING1*/ },