[wb_acq_core] Mixed data when aborting acquisition

[lerwys]

Problem: When aborting an acquisition, we can stay in an unrecoverable state: some data from the acquisition will be written in the previous channel address. This happens because when not completing the current transaction, the AXI datamover module (if not properly halt/rst) will wait for new data to come.
This data will be written on the previous burst address until it finishes.

Solution: Properly halt the AXI datamover module and then reset it to clear the halt signals.