remoteproc: k3-{m4/dsp}: Add a void ptr member in rproc internal struct

remoteproc: k3-{m4/dsp}: Add a void ptr member in rproc internal struct

Introduce a void pointer in the k3_{m4/dsp}_rproc internal data
structure which can be used to point to any private data needed by the
driver. Currently, the M4/DSP drivers do not have any private data, so
the pointer can be left pointing to NULL.

This is done to align the data structures with R5 driver which can be
factored out at a later stage.

Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
Tested-by: Judith Mendez <jm@ti.com>
Reviewed-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20250513054510.3439842-10-b-padhi@ti.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>