lpc32xx: devkit3250: update board configuration file

The change updates DevKit3250 board powerd by NXP LPC3250 SoC:
* due to increased resulting U-boot image size give more space to
  store loaded and relocated versions,
* add DMA support, which is used by NAND SLC driver,
* add NXP OHCI and PHY drivers to the image,
* add USB, JFFS and FAT commands.

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