linux-phytec-ti

mtd: Get rid of unused fields in struct erase_info

Some fields are not used by MTD drivers, users or core code. Moreover,
those fields are not documented, so get rid of them to avoid any
confusion.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>