dmaengine: sudmac: remove unused driver

SUDMAC driver was introduced in v3.10 but was never integrated for use
by any platform. As it is unused remove it.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>