Few times, core1 was scheduled to boot first before core0, which leads
to error:

'k3_r5_rproc_start: can not start core 1 before core 0'.

This was happening due to some scheduling between prepare and start
callback. The probe function waits for event, which is getting
triggered by prepare callback. To avoid above condition move event
trigger to start instead of prepare callback.

Fixes: 61f6f684 ("remoteproc: k3-r5: Wait for core0 power-up before powering up core1")
Signed-off-by: Udit Kumar <u-kumar1@ti.com>
[ Applied wakeup event trigger only for Split-Mode booted rprocs ]
Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240820105004.2788327-1-b-padhi@ti.comSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>