dmaengine: fsl-edma: add address for channel mux register in fsl_edma_chan

iMX95 move channel mux register to management page address space. This
prepare to support iMX95.

Add mux_addr in struct fsl_edma_chan. No function change.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20231221153528.1588049-4-Frank.Li@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>