remoteproc: k3: Refactor .start rproc ops into common driver

remoteproc: k3: Refactor .start rproc ops into common driver

The k3_dsp_rproc_start() function sets the boot vector and releases the
reset on the remote processor. Whereas, the k3_m4_rproc_start() function
only needs to release the reset.

Refactor the k3_m4_rproc_start() into ti_k3_common.c as k3_rproc_start()
and align the DSP and M4 drivers to invoke this common function when
releasing the reset on the remote processor.

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/20250513054510.3439842-28-b-padhi@ti.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>