imx: ventana: refactor board-specific dt fixups (no functional change)

Re-factor the board-specific dt fixups so that they are easier to follow
and extend in the future:
 - use defines for DT paths
 - use switch/case per board
 - order models numerically

There is no functional change in the code

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
1 file changed