staging: vchiq: Get rid of vchi

All the functions that vchi currently provides are a 1:1 mapping to its
vchiq counterparts. Get rid of vchi altogether and use vchiq's on all
services.

In the process also get rid of the vchi directory, as the only remaining
file was a TODO file, which now lives in the parent directory.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200629150945.10720-44-nsaenzjulienne@suse.de


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