remoteproc: keystone: Use devm_rproc_alloc() helper

Use the device lifecycle managed allocation function. This helps prevent
mistakes like freeing out of order in cleanup functions and forgetting to
free on error paths.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240802182300.244055-2-afd@ti.com


Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>