dmaengine: fsl-edma: clean up EXPORT_SYMBOL_GPL in fsl-edma-common.c

Exported functions in fsl-edma-common.c are only used within
fsl-edma.c and mcf-edma.c. Global export is unnecessary.

This commit removes all EXPORT_SYMBOL_GPL in fsl-edma-common.c,
and renames fsl-edma.c and mcf-edma.c to maintain the same
final module names as before, thereby simplifying the codebase.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20230821161617.2142561-3-Frank.Li@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>