mtd: rawnand: txx9ndfmc: Drop if block with always false condition

txx9ndfmc_remove() is only called after txx9ndfmc_probe() completed
successfully. In this case platform_set_drvdata() was called with a
non-NULL argument and so platform_get_drvdata() won't return NULL.

Simplify by removing the if block with the always false condition.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20231102220246.3336154-9-u.kleine-koenig@pengutronix.de