When McBSP is configured in threshold mode we can use sDMA packet mode in
all cases.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: NJanusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>