remoteproc: imx_rproc: Make detach operation platform-specific

remoteproc: imx_rproc: Make detach operation platform-specific

Refactor the detach logic to support platform-specific implementations via
the dcfg->ops->detach callback. Allow finer control over detach behavior
depending on the remote processor management method, and make it easier
to add detach support for new SoCs.

The previous hardcoded SCU API detach logic is now moved into a dedicated
imx_rproc_scu_api_detach() function, and registered via the plat ops
structure. The generic imx_rproc_detach() now delegates to the
platform-specific handler if available.

Also, the dcfg->method check with IMX_RPROC_SCU_API is removed.

No functional changes.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20251024-imx_rproc_c4-v4-2-af83ed3fdbba@nxp.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>