Update fspi node compatibles of LX2160A-RDB to "jedec,spi-nor" for
automatic detection of flash.

This also helps in fixing below warning:
spi-nor spi0.0: found mt35xu512aba, expected m25p80
spi-nor spi0.1: found mt35xu512aba, expected m25p80
Signed-off-by: Kuldeep Singh <kuldeep.singh@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>