mtd: nand: Export nand_reset() symbol

mtd: nand: Export nand_reset() symbol

commit b9bb98424c51437973b854691aa1e9b2bfd348f5 upstream.

Commit 6e532afaca8e ("mtd: nand: atmel: Add PM ops") started to use the
nand_reset() function which was not yet exported by the NAND framework
(because it was only used internally before that). Export this symbol
to avoid build errors when the driver is enabled as a module.

Fixes: 6e532afaca8e ("mtd: nand: atmel: Add PM ops")
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>