staging: dgnc: Remove unnecessary 'return' statement

This commit fixes the checkpath warning 'void function return
statements are not generally useful' caused by the 'return' at the end
of 'void' function.

Signed-off-by: Konrad Zapalowicz <bergo.torino@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>