staging: comedi: ni_tio_internal: export {read, write)_register()

Move these inline functions out of the header and export them instead.
These functions have pretty generic names, rename them.

Fix the checkpatch.pl issues:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
CHECK: Avoid crashing the kernel - try using WARN_ON & recovery code
       rather than BUG() or BUG_ON()

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