spi: atcspi200: fix use-after-free when driver unbind

spi: atcspi200: fix use-after-free when driver unbind

DMA resource is initialized after SPI controller registration. So
when driver unbind, this can trigger a use-after-free when DMA is
torn down while the controller is still alive and triggers DMA transfers.

Fixes: 34e3815ea459 ("spi: atcspi200: Add ATCSPI200 SPI controller driver")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Link: https://patch.msgid.link/20260417-atcspi-v1-1-854831667d63@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>