Remove the watermark support. A future commit will add support for having
enqueue functions return the amount of free space in the ring, which will
allow applications to implement their own watermark checks, while also
being more useful to the app.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
77dd306427