spi: oc-tiny: switch to managed controller allocation

In the Linux kernel, the following vulnerability has been resolved: spi: oc-tiny: switch to managed controller allocation The controller is allocated with the non-managed spi_alloc_host() while the interrupt is registered with devm_request_irq(). During removal, spi_bitbang_stop() only unregisters the controller; the subsequent spi_controller_put() then frees the controller together with its embedded driver-private devdata, which is the IRQ handler's dev_id. The devm_request_irq() release action (free_irq()), which drains the handler, does not run until after .remove() returns. A late or latched interrupt can therefore reach tiny_spi_irq() and dereference already-freed memory (e.g. hw->base). Switch to devm_spi_alloc_host() so that the devres LIFO order releases the controller only after free_irq() has drained the handler, and drop the now-redundant spi_controller_put() from .remove(). The probe error path is simplified to direct returns. This issue was found by an in-house static analysis tool.