staging: vchiq_arm: Create keep-alive thread during probe

Creating the keep-alive thread in vchiq_platform_init_state have
the following advantages:
- abort driver probe if kthread_create fails (more consistent behavior)
- make resource release process easier

Since vchiq_keepalive_thread_func is defined below
vchiq_platform_init_state, the latter must be moved.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20250309125014.37166-5-wahrenst@gmx.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>