dmaengine: dw-axi-dmac: support DMAX_NUM_CHANNELS > 8

Added support for DMA controller with more than 8 channels.
DMAC register map changes based on number of channels.

Enabling DMAC channel:
DMAC_CHENREG has to be used when number of channels <= 8
DMAC_CHENREG2 has to be used when number of channels > 8

Configuring DMA channel:
CHx_CFG has to be used when number of channels <= 8
CHx_CFG2 has to be used when number of channels > 8

Suspending and resuming channel:
DMAC_CHENREG has to be used when number of channels <= 8 DMAC_CHSUSPREG
has to be used for suspending a channel > 8

Signed-off-by: Pandith N <pandith.n@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Link: https://lore.kernel.org/r/20211001140812.24977-2-pandith.n@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>