ARM: dts: sunxi: Add OLinuXino Lime2 eMMC to the Makefile

commit 27dd9af6 ("ARM: dts: sunxi: Add a olinuxino-lime2-emmc")
added the new emmc equipped lime2 but forgot its Makefile.

This patch adds an entry to the Makefile.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Olof Johansson <olof@lixom.net>