staging: comedi: usbdux: remove redundant initialization of fx2delay

Variable fx2delay is being initialized to a value that is never read
and is being re-assigned a few statements later. The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>