spi: rockchip-sfc: Fix double-free in remove() callback

spi: rockchip-sfc: Fix double-free in remove() callback

The driver uses devm_spi_register_controller() for registration, which
automatically unregisters the controller via devm cleanup when the
device is removed. The manual call to spi_unregister_controller() in
the remove() callback can lead to a double-free.

And to make sure controller is unregistered before DMA buffer is
unmapped, switch to use spi_register_controller() in probe().

Fixes: 8011709906d0 ("spi: rockchip-sfc: Support pm ops")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Link: https://patch.msgid.link/20260310-sfc-v2-1-67fab04b097f@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>