spi: imx: fix use-after-free on unbind

spi: imx: fix use-after-free on unbind

The SPI subsystem frees the controller and any subsystem allocated
driver data as part of deregistration (unless the allocation is device
managed).

Take another reference before deregistering the controller so that the
driver data is not freed until the driver is done with it.

Fixes: 307c897db762 ("spi: spi-imx: replace struct spi_imx_data::bitbang by pointer to struct spi_controller")
Cc: stable@vger.kernel.org	# 5.19
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260324082326.901043-2-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>