dmaengine: dw-edma: Rename wr(rd)_ch_cnt to ll_wr(rd)_cnt in struct dw_edma_chip

The struct dw_edma contains wr(rd)_ch_cnt fields. The EDMA driver gets
write(read) channel number from register, then saves these into dw_edma.
The wr(rd)_ch_cnt in dw_edma_chip actually means how many link list memory
are available in ll_region_wr(rd)[EDMA_MAX_WR_CH]. Rename it to
ll_wr(rd)_cnt to indicate actual usage.

Link: https://lore.kernel.org/r/20220524152159.2370739-5-Frank.Li@nxp.com


Tested-by: Serge Semin <fancer.lancer@gmail.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>