staging: vc04_services: Remove vchiq_send_remote_release()

Remove unused function vchiq_send_remote_release.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>