staging: comedi: comedi_compat32.c: align some comments

Align some comments attached to members of the 32-bit compatibility
structure definitions.  These comments describe the original pointer
types that are being represented by a `compat_uptr_t`.

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>