ARM: dts: lpc4350-hitex-eval: add emc pins and static memory devices

Setup the emc pins used by external memory devices and add
configuration for the devices found on the Hitex eval board.

The Hitex eval board has a NOR Flash attached to chip select 0
and 512 kB of SRAM on chip select 2.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Olof Johansson <olof@lixom.net>