Certain state flags bit combinations are not checked and not handled
correctly. Plus, do not log a normal underrun situation where there is
no frame drop.

Link: https://lore.kernel.org/r/20200226224022.24518-17-hmadhani@marvell.com


Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>