lpc32xx: devkit3250: add spl build support

lpc32xx: devkit3250: add spl build support

The change adds SPL build support to Timll DevKit3250 board, the
generated SPL image can be uploaded over UART5, JTAG or stored on
NAND. SPL is designed to load U-boot image from NAND.

All new NAND chip defines in board configuration are needed by
SPL NAND "simple" framework, the framework is used to reduce
potentially duplicated code from LPC32xx SLC NAND driver.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>