board: fsl: lx2160ardb: add api for obtaining board revision

Add new API for obtaining board revision and trigger the i2c node
fixup with this new API.

Signed-off-by: Florin Chiculita <florinlaurentiu.chiculita@nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>