staging: vchi: Merge vchi_msg_queue() into vchi_queue_kernel_message()

There are no gains from that extra indirection level. Also, get rid of
the function description, the whole file will disappear soon.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200527115400.31391-5-nsaenzjulienne@suse.de


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