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

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

The .prepare rproc ops implementations in TI K3 DSP and M4 remoteproc
drivers deasserts the local and module reset of the processor to allow
firmware loading into internal memory.

Refactor the implementations into the ti_k3_common.c driver as
k3_rproc_prepare() and register this common function as .prepare ops in
the DSP and M4 drivers.

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/20250513054510.3439842-26-b-padhi@ti.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>