dmaengine: qcom: bam_dma: use correct pipe FIFO size

The pipe fifo size register must instruct the bam hw
how many hw descriptors can be pushed to fifo. Currently
we instruct the hw with 32KBytes but wrap the tail in
bam_start_dma in BAM_P_EVNT_REG on 4095 i.e. 32760. This
leads to stalled transactions when the tail wraps.

Fix this by use the correct fifo size in BAM_P_FIFO_SIZES
register i.e. 32K - 8.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>