soundwire: cadence_master: filter out bad interrupts

If somehow we read the interrupt status while the IP is not powered
the result is probably undefined or 0xffffffff. We do know that some
of the bits are reserved and read as zero, so use as a filter to
discard invalid configurations.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200110215731.30747-2-pierre-louis.bossart@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>