[PATCH] ARM: OMAP: FB support for OMAP2

included in this FB patch:
- OMAP2 support with overlay, colorkey handling
- the palmte patch posted by Romain Goyet. The palette loading is
  changed a bit, so that it works ok with other platforms as well.
- registering the FB device through plat-omap/devices.c instead of doing
  it from the driver itself. Boards have to specify the OMAP_TAG_LCD
  config in the related board-*.c with in order to have FB support.
- pixel clock divider calculation based on the panel->pixel_clock
  instead of the wired panel->pcd
- support for external controllers both on SOSSI (OMAP1) and
  RFBI (OMAP2), kudos to Juha for this
- removal of the OMAP1 2D gfx stuff, it didn't really improve the
  performance:(
- double buffering IOCTL API, as this can be done in a more standard
  way through FBIOPUT_VSCREENINFO
- update of the affected omap_*_defconfigs
- minor formatting changes and typo fixes

Still TODO:
- OMAP2 Rotation, scaling of video planes
- OMAP2 digit-out (aka tv-out)
- moving the frame buffer to an alternative locating (onchip SRAM)

I tested it with H2 and H4 but it might break on other OMAP1 boards as
there were changes also in the old parts.