Add Synopsys eDMA IP driver maintainer.

This driver aims to support Synopsys eDMA IP and is normally distributed
along with Synopsys PCIe EndPoint IP (depends of the use and licensing
agreement).
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>