staging: vc04_services: Drop declaration of vchi_crc_control()

There is no definition for this unused function, so drop its prototype.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>