spi: cadence-xspi: Drop useless assignment to NULL

Static structs are initialized with zeros for unspecified fields. So
there is no advantage to explicitly initialize .remove with NULL and the
assignment can be dropped without side effects.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231105143932.3722920-2-u.kleine-koenig@pengutronix.de


Signed-off-by: Mark Brown <broonie@kernel.org>