remoteproc: imx_dsp_rproc: Simplify IMX_RPROC_RESET_CONTROLLER switch case

remoteproc: imx_dsp_rproc: Simplify IMX_RPROC_RESET_CONTROLLER switch case

Introduce imx_dsp_rproc_reset_ctr_{start, stop, detect_mode}() helper
functions for i.MX variants using IMX_RPROC_RESET_CONTROLLER to manage
remote processors.

Allows the removal of the IMX_RPROC_RESET_CONTROLLER switch-case blocks
from imx_dsp_rproc_[start,stop,detect_mode](), resulting in cleaner and
more maintainable code.

No functional changes.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Tested-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20251119-imx-dsp-2025-11-19-v4-10-adafd342d07b@nxp.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>