omap3: pandora: board file updates for .33

Pandora board file updates:
- change keycodes of game buttons
  it was decided not to use ABXY layout by the developers.
- drop i2c bus 3 speed to 100kHz
  this is needed for battery monitoring chip to work reliably.
- drop pandora_lcd platform_device
  the older DSS driver was never functional on l-o or mainline
  kernels due to missing panel driver, so remove unneeded
  pandora_lcd platform_device. This also removes last OMAP_TAG
  from the board file.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>