The Atmel MPDDR controller support LPDDR2 and LPDDR3 memories, add their
types.

Cc: <stable@vger.kernel.org> # 4.4+
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NSebastian Reichel <sre@kernel.org>