[U-Boot] TI:OMAP: Following patches adds support for Beagle REV C4

[Khasim Syed Mohammed]

Hi Sandeep / Denx,

The following patch series adds support for Beagle REV C4 with
following functionality

These patches will add :
- I2C bus switching logic
- Support to enable 720 Mhz ARM MPU clock on REV C4 boards
- Enables DSS for background on DVI-D and color bar on S-video with
out using FRAMEBUFFERs
- Rev Detection patch from Dirk.

It has been tested on Beagle board REV B5, REV C2/C3 and REV C4.

Regards,
Khasim