mtd: nand: drop kernel-doc notation for a deleted function parameter

mtd: nand: drop kernel-doc notation for a deleted function parameter

Remove kernel-doc notation for a deleted function parameter to prevent
a kernel-doc warning:

../drivers/mtd/nand/raw/nand_base.c:603: warning: Excess function parameter 'mtd' description in 'panic_nand_wait'

Fixes: f1d46942e823 ("mtd: rawnand: Pass a nand_chip object to chip->waitfunc()")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>