dmaengine: Remove unused definition of DMA_MAX_COOKIE
As of commit commit f04cd40701deace2efb9edd7120e59366bda2118 ("fsldma: fix
controller lockups"), its last (and only ever) user is gone.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>