mtd: nand: Update mtd.name assignment type to u64 for IFC, eLBC

mtd.name is assigned to IFC NAND physical address. Assignment type is u32.
It is not providing correct physical address of IFC NAND.

Update assignment type to u64.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>