nand: mxc: Switch NAND SPL to generic SPL

This also fixes support for mx31pdk and tx25, which had been broken by commit
e05e5de7fae5bec79617e113916dac6631251156.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
20 files changed