spi: mchp-pci1xxxx: DMA support for copying data to and from SPI Buf

pci1xxxx_spi_transfer_with_dma adds DMA support to copy the data between
host cpu buffer and SPI IO Buffer.
On DMA Completion interrupt, the next SPI transaction is initiated in isr.
Helper functions pci1xxxx_spi_setup, pci1xxxx_spi_setup_dma_from_io,
pci1xxxx_spi_setup_dma_to_io and pci1xxxx_start_spi_xfer are added for
setting up spi, setting up dma operations, and to start spi transfer
respectively. In the existing implementation, codes are replaced with
helper functions wherever applicable.
Signed-off-by: Thangaraj Samynathan <thangaraj.s@microchip.com>
Link: https://lore.kernel.org/r/20240207080621.30742-3-thangaraj.s@microchip.comSigned-off-by: Mark Brown <broonie@kernel.org>