tests: add more test descriptions

Add more test descriptions based on exiting comments.

Signed-off-by: Thomas Wood <thomas.wood@intel.com>

tests/gem_ring_sync_copy.c

@@ -55,6 +55,8 @@
 #include "intel_batchbuffer.h"
 #include "intel_chipset.h"
 
+IGT_TEST_DESCRIPTION("Ensure inter-ring dependencies are respected.");
+
 #define WIDTH	512
 #define HEIGHT	512
 #define NUM_BUSY_BUFFERS 32