staging: vchiq: Introduce vchiq_validate_params()

When adding a new service validate the configuration parameters
provided, and remove unnecessary checks in vchi, now that we have
validated service's config.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200629150945.10720-23-nsaenzjulienne@suse.de


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