spi: atmel-quadspi: Free resources even if runtime resume failed in .remove()

In the Linux kernel, the following vulnerability has been resolved: spi: atmel-quadspi: Free resources even if runtime resume failed in .remove() An early error exit in atmel_qspi_remove() doesn't prevent the device unbind. So this results in an spi controller with an unbound parent and unmapped register space (because devm_ioremap_resource() is undone). So using the remaining spi controller probably results in an oops. Instead unregister the controller unconditionally and only skip hardware access and clk disable. Also add a warning about resume failing and return zero unconditionally. The latter has the only effect to suppress a less helpful error message by the spi core.