drm/i915: Avoid format string expansion from engine names

While highly unlikely, this makes sure that the string built from
engine names won't be processed as a format string.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170411045630.GA6612@beast

drivers/gpu/drm/i915/intel_hangcheck.c

@@ -407,7 +407,7 @@ static void hangcheck_declare_hang(struct drm_i915_private *i915,
 				 "%s, ", engine->name);
 	msg[len-2] = '\0';
 
-	return i915_handle_error(i915, hung, msg);
+	return i915_handle_error(i915, hung, "%s", msg);
 }
 
 /*