drm/i915: Wedged engine mask makes more sense in hex

In decimal its just a weird big number, while in hex can actually log
which engines were requested to be wedged.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180228171844.20006-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3977,7 +3977,8 @@ i915_wedged_set(void *data, u64 val)
 		engine->hangcheck.stalled = true;
 	}
 
-	i915_handle_error(i915, val, "Manually setting wedged to %llu", val);
+	i915_handle_error(i915, val, "Manually set wedged engine mask = %llx",
+			  val);
 
 	wait_on_bit(&i915->gpu_error.flags,
 		    I915_RESET_HANDOFF,