The patch is needed since there is some IBS code in add_ibs_begin()
that handles more than one sample per iteration. This requires calling
get_slots() during each loop.

This fixes the current problem, but a proper solution that reworks the
cpu buffer synchronization is needed here in the future.
Signed-off-by: NBarry Kasindorf <barry.kasindorf@amd.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>