mtd: spi-nor: fix memory leak when using debugfs_lookup()

[ Upstream commit ec738ca1 ]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To solve this, remove the
lookup and create the directory on the first device found, and then
remove it when the module is unloaded.

Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20230208160230.2179905-1-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>