drm/i915/selftests: Run MI_BB perf selftests on SNB

SNB does have the RING_TIMESTAMP register on the RCS engine.
Run the MI_BB perf tests on it.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221031135703.14670-5-ville.syrjala@linux.intel.comReviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

drivers/gpu/drm/i915/gt/selftest_engine_cs.c

@@ -125,7 +125,7 @@ static int perf_mi_bb_start(void *arg)
 	enum intel_engine_id id;
 	int err = 0;
 
-	if (GRAPHICS_VER(gt->i915) < 7) /* for per-engine CS_TIMESTAMP */
+	if (GRAPHICS_VER(gt->i915) < 6) /* for per-engine CS_TIMESTAMP */
 		return 0;
 
 	perf_begin(gt);
@@ -135,6 +135,9 @@ static int perf_mi_bb_start(void *arg)
 		u32 cycles[COUNT];
 		int i;
 
+		if (GRAPHICS_VER(engine->i915) < 7 && engine->id != RCS0)
+			continue;
+
 		intel_engine_pm_get(engine);
 
 		batch = create_empty_batch(ce);
@@ -249,7 +252,7 @@ static int perf_mi_noop(void *arg)
 	enum intel_engine_id id;
 	int err = 0;
 
-	if (GRAPHICS_VER(gt->i915) < 7) /* for per-engine CS_TIMESTAMP */
+	if (GRAPHICS_VER(gt->i915) < 6) /* for per-engine CS_TIMESTAMP */
 		return 0;
 
 	perf_begin(gt);
@@ -259,6 +262,9 @@ static int perf_mi_noop(void *arg)
 		u32 cycles[COUNT];
 		int i;
 
+		if (GRAPHICS_VER(engine->i915) < 7 && engine->id != RCS0)
+			continue;
+
 		intel_engine_pm_get(engine);
 
 		base = create_empty_batch(ce);