DMA: shdma: remove private and unused defines from a global header

Macros, named like TEND or SAR lack a namespace and are too broadly named
for a global header. Besides, they aren't needed globally. Move them to
where they belong - into the driver. Some other macros aren't used at all,
remove them.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>