Support for seven segment display

[Jaghathiswari Rankappagounder Natarajan]

The are 3 patches included:

The first patch is a character device driver which implements the user-space 
API for letting a user write to the display including any conversion methods
necessary to map the user input to a 7-segment display.

The second patch is a platform device driver which provides an API for
displaying on a 7-segment display, and implements the required bit-banging.
The hardware assumed is 74HC164 wired to two 7-segment displays.

The third patch adds clock, data and clear signal lines to control 
seven segment display on zaius platform

Please provide feedback.

Thanks,
Jagha