staging: comedi: don't rely on comedidev.h to include headers

comedidev.h is the main kernel header for comedi. Every comedi
driver includes this header which then includes a number of
<linux/*> headers. All the drivers need <linux/module.h> and some
of them need <linux/delay.h>. The rest are not needed by any of
the drivers.

Remove all the includes in comedidev.h except for <linux/dma-mapping.h>,
which is needed to pick up the enum dma_data_direction for the
comedi_subdevice definition, and "comedi.h", which is the uapi
header for comedi.

Add <linux/module.h> to all the comedi drivers and <linux/delay.h>
to the couple that need it.

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