mtd: mtdraw: drop ioctl callback for mtdraw device
Do not call mtd_ioctl for mtdraw devices. mtd_ioctl will derefence
the priv pointer to a struct mtd_info whereas with mtdraw devices it will be
a struct mtdraw pointer. We do not need ioctls for mtdraw devices, so drop
it instead of fixing it.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>