staging: comedi: comedi_compat32.c: absorb raw_ioctl()

`comedi_compat_ioctl()` just calls static inline function `raw_ioctl()`
with the same parameters (although the former returns a `long` and the
latter returns an `int`).  Since `raw_ioctl()` is not called from
anywhere else, just absorb its body into `comedi_compat_ioctl()`.

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