spi: spi-qpic-snand: unregister ECC engine on probe error and device remove

In the Linux kernel, the following vulnerability has been resolved:

spi: spi-qpic-snand: unregister ECC engine on probe error and device remove

The on-host hardware ECC engine remains registered both when the spi_register_controller() function returns with an error and also on device removal.

Change the qcom_spi_probe() function to unregister the engine on the error path, and add the missing unregistering call to qcom_spi_remove() to avoid possible use-after-free issues.