[PATCH] MTD: fix last kernel-doc warning

Fix the last current kernel-doc warning:
Warning(/var/linsrc/linux-2619-rc3g5//include/linux/mtd/nand.h:416): No description found for parameter 'write_page'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>