mtd: nand: embed an mtd_info structure into nand_chip

mtd: nand: embed an mtd_info structure into nand_chip

Currently all NAND controller drivers are providing both the mtd_info and
nand_chip struct and then let the NAND subsystem to initialize a few
things before registering the mtd instance to the MTD layer.
Embed an mtd_info field into nand_chip to add some consistency to all NAND
controller drivers.
This change will also help factorizing boilerplate code copied in all NAND
drivers.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>