mtd: nand: add fields for JEDEC in nand_chip

Add the jedec_version field, and add an anonymous union which
contains the nand_onfi_params and nand_jedec_params.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>