drm/i915: Show CCID in engine dumps

For debugging context issues, knowing what context the GPU is
loading/using is helpful.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180614094103.18025-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -1273,6 +1273,8 @@ static void intel_engine_print_registers(const struct intel_engine_cs *engine,
 		&engine->execlists;
 	u64 addr;
 
+	if (engine->id == RCS && IS_GEN(dev_priv, 4, 7))
+		drm_printf(m, "\tCCID: 0x%08x\n", I915_READ(CCID));
 	drm_printf(m, "\tRING_START: 0x%08x\n",
 		   I915_READ(RING_START(engine->mmio_base)));
 	drm_printf(m, "\tRING_HEAD:  0x%08x\n",