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@xxxxxxx>