HH LCD and I2C board

These are mainly additions to support the external LCD provided by the
hhlcd28a device driver:

- Defconfig put into handhold_defconfig as a diff to duovero_defconfig.
- i2c bus speed on bus #2 reduced to 100kHz as the external PIC cannot
  handle 400kHz.
- Changes to board-duovero.c to add the platform data from hhlcd28a.h
  and the proper spi_board_info structures. Note that 10MHz here works
  out as the nearest lowest division of 48MHz from the OMAP4430's SPI clock.
  Which is actually 6MHz. There is no define boundaries around the spi board
  info blocks and it should really depend on FB_HHLCD.
- Changes to video/Kconfig to add the FB_HHLCD option.