staging: comedi: ni_daq_dio24: remove some unnecessary includes

This driver does not use anything from the interrupt.h, slab.h,
and ioport.h headers. Don't bother including them.

For aesthetic reasons, move the include of the comedi specific
8255.h header to the end of the includes.

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>