staging: vchiq_core: rework vchiq_get_config

The function is overly complicated for what it's ultimately achieving.
It's simply filling up a structure.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>