commit 7f66c2f9 upstream.

Handle previous allocation failures when freeing device memory
Signed-off-by: Simon Graham <simon.graham@virtualcomputer.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>