soundwire: cadence: export sdw_cdns_bpt_find_bandwidth

soundwire: cadence: export sdw_cdns_bpt_find_bandwidth

Currently, we calculate the required bandwidth after the PDI buffer size
is calculated. However as we need to add some fake frame to align the
data block size, the final PDI size and the frame number will change.
Besides, we need the required bandwidth to decide the DMA channel number
and the channel number will be used to calculate the data block size.
Therefore, we calculate the required bandwidth and export a helper for
the caller to get the required bandwidth.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://patch.msgid.link/20251014031450.3781789-5-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>