ZOOM2 detect the version of the zoom2 board at runtime.

There are currently 3 versions of the zoom2 board.
The production board, that is currently being released.
The beta board, similar in form to the production board but not released.
The alpha board, a set of PCBs with a very limited circulation.

GPIO 94 is used to determine the version of the board. If GPIO 94 is clear,
the board is a production board, otherwise it is a beta board.

The alpha board will likely be mistaken for a beta board.  An alpha board
was unavailible for testing.

This has been tested on the beta and production boards.

Signed-off-by: Tom Rix <Tom.Rix@windriver.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>