dmaengine: dw-edma: Rename dw_edma_core_ops structure to dw_edma_plat_ops

The dw_edma_core_ops structure contains a set of the operations:
device IRQ numbers getter, CPU/PCI address translation. Based on the
functions semantics the structure name "dw_edma_plat_ops" looks more
descriptive since indeed the operations are platform-specific. The
"dw_edma_core_ops" name shall be used for a structure with the IP-core
specific set of callbacks in order to abstract out DW eDMA and DW HDMA
setups. Such structure will be added in one of the next commit in the
framework of the set of changes adding the DW HDMA device support.

Anyway the renaming was necessary to distinguish two types of
the implementation callbacks:
1. DW eDMA/hDMA IP-core specific operations: device-specific CSR
setups in one or another aspect of the DMA-engine initialization.
2. DW eDMA/hDMA platform specific operations: the DMA device
environment configs like IRQs, address translation, etc.

Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20230520050854.73160-2-cai.huoqing@linux.dev
Signed-off-by: Vinod Koul <vkoul@kernel.org>