staging: comedi: ni_mio_common: absorb mite_handle_b_linkc()

Simplfy the LINKC handing by removing the helper function and moving
the mite_sync_dma() into the main interrupt handler.

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>