i915/gt/selftests: Disable lrc_timestamp test

This test was designed to isolate a bug in tigerlake and dg2 hardware.
The bug was found and fixed in newer generations.
Since we won't support any new hardware with this driver, the test
should now be turned off in the CI to not pollute it with random failures
on previous hardware.

For reference, the issue has been discssued here[*].

[*] https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13697

Signed-off-by: Mikolaj Wasiak <mikolaj.wasiak@intel.com>
Reviewed-by: Chris Wilson <chris.p.wilson@linux.intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/uxxb22n667zb3aic6zs4mr2krv5zavav5v2zjgqnhnabgxgzif@4icszicjakex

Author: mwasiakint

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

@@ -7,6 +7,7 @@
 
 #include "gem/i915_gem_internal.h"
 
+#include "i915_drv.h"
 #include "i915_selftest.h"
 #include "intel_engine_heartbeat.h"
 #include "intel_engine_pm.h"
@@ -858,6 +859,14 @@ static int live_lrc_timestamp(void *arg)
 		U32_MAX,
 	};
 
+	/*
+	 * This test was designed to isolate a hardware bug.
+	 * The bug was found and fixed in future generations but
+	 * now the test pollutes our CI on previous generation.
+	 */
+	if (GRAPHICS_VER(gt->i915) == 12)
+		return 0;
+
 	/*
 	 * We want to verify that the timestamp is saved and restore across
 	 * context switches and is monotonic.