omap: Fix keymap for zoom2 according to matrix keypad framwork

Interpretation of 'row' and 'col' got reversed in matrix keymap
framework. Also last element '0', present in keymap array, is no
more needed.
Correcting zoom2 keyboard keymap accordingly.

Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>