staging: comedi: das1800: move dma transfer 'size' to dma descriptor

For asethetics, move the variable that holds the dma transfer 'size' into
the dma descriptor.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/staging/comedi/drivers/das1800.c
Simple merge