staging: comedi: usbdux: remove redundant initialization of val

staging: comedi: usbdux: remove redundant initialization of val

The early initialization of val is redundant as the value is never
read and is updated inside a for-loop. Remove the initialization
and move the declaration and initialization to the for-loop scope.
Cleans up clang warning:

drivers/staging/comedi/drivers/usbdux.c:812:15: warning: Value stored
to 'val' during its initialization is never read

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>