comedi: ni_routing: tools: Update due to moved COMEDI headers

Building of the tools for converting the NI routing information between
CSV files (for maintenance) and C files (for building) was broken by the
move of the main COMEDI header files to "include/uapi/linux/" and
"include/linux/". (These tools are not built as part of the normal
kernel build process.) Fix it in the Makefile.

A slight niggle is that `#include <linux/comedi.h>` needs to work when
compiling the `convert_c_to_py` program, but it cannot use a `-I` option
referring to the "uapi" include directory because that interferes with
inclusion of other system headers. So it uses `-I.` and makes a local
copy (actually a symbolic link) as "./linux/comedi.h".

Also remove some unneeded cruft such as the `-D"BIT(x)=(1<<(x))"`
preprocessor flag.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20211117120604.117740-3-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: comedi: move out of staging directory

The comedi code came into the kernel back in 2008, but traces its
lifetime to much much earlier. It's been polished and buffed and
there's really nothing preventing it from being part of the "real"
portion of the kernel.

So move it to drivers/comedi/ as it belongs there.

Many thanks to the hundreds of developers who did the work to make this
happen.

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Link: https://lore.kernel.org/r/YHauop4u3sP6lz8j@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>