staging: vc04_services: make a couple of pointers static

The pointers vchiq_dbg_dir and vchiq_dbg_clients are local to the
source and do not need to be in global scope, so make them static.

Cleans up sparse warnings:
warning: symbol 'vchiq_dbg_dir' was not declared. Should it be static?
warning: symbol 'vchiq_dbg_clients' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>