ARM: imx: Remove i.MX35 board files

i.MX35 has basic device tree support.

To achieve the goal of converting all i.MX SoCs to a
devicetree-only platform, remove imx35 board files.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>