dt-bindings: imx-ocotp: Add i.MX6ULL/ULZ support

Since the i.MX6ULL/ULZ only supports 8 OTP banks we need to introduce a new
compatible.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>