mtd: Add some fallbacks for add/del_mtd_device

This allows using these functions without ifdefs. OneNAND depends on MTD,
so this ifdef was redundant in the first place.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
3 files changed