Add Synopsys xData IP driver maintainer.

This driver aims to support Synopsys xData IP and is normally distributed
along with Synopsys PCIe EndPoint IP as a PCIe traffic generator (depends
of the use and licensing agreement).
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/c8fb9af0ba8c86c5cf8afbfc0eb07fc99a642270.1617016509.git.gustavo.pimentel@synopsys.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>