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

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

The .attach rproc ops implementations in TI K3 R5, DSP and M4 drivers
are NOPs. Refactor the implementations into ti_k3_common.c driver
as k3_rproc_attach() and register this common function as .attach ops in
R5, 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/20250513054510.3439842-30-b-padhi@ti.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>