Activate Fusion touchscreen driver. Use GPIO 5/6 as pen down/reset
GPIO and provide a helper function to free the GPIO before the
driver requests them.

Fusion touchscreen driver now uses platform data to do GPIO
initialization by itself. Make use of this by providing GPIO numbers
instead of doing initialization in the board initialization.

Allow to change clock polarity for RGB display output using the
keywords outputen/pixclockpol/vsync and hsync. Add them right
after the driver specification, use 0/1 to specifiy high/low
polarity, e.g. video=tegrafb0:pixclockpol:1,800x480

Remove special clocks for Tegra 2, but use backup clock source
instead. This allows to run all common used resolution within
the drivers -1/+9% allowed band for pixelclock exactness.

Remove TEGRA_FB_VGA defines and use VGA as default. Since initial
mode is now configureable through kernel cmd line parameter, we
don't need those compile time helpers.

Use modedb to set mode on framebuffer/display controller for
Tegra 20 based module Colibri T20 too.

In order to find a viable resolution we not only parse VESA mode,
we also parse CEA (multimedia) modes and our own small modedb (for
specific touch screens).

Use new modedb based framebuffer settings by defining default_mode
in the display controllers platform data. Also impelmented the
fallback logic to this default_mode in case no kernel cmd line
parameter was set.

Allow to specify framebufffer videomode using kernel command line
parameters. NVIDIAs binary X driver later on picks up those settings
and start X with current mode settings, if no EDID data are available.