MAINTAINERS: Add an additional maintainer to the AMD XGBE driver

Add Shyam Sundar S K as an additional maintainer to support the AMD XGBE
network device driver.

Cc: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/db367f24089c2bbbcd1cec8e21af49922017a110.1657751501.git.thomas.lendacky@amd.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -1040,6 +1040,7 @@ F:	arch/arm64/boot/dts/amd/
 
 AMD XGBE DRIVER
 M:	Tom Lendacky <thomas.lendacky@amd.com>
+M:	"Shyam Sundar S K" <Shyam-sundar.S-k@amd.com>
 L:	netdev@vger.kernel.org
 S:	Supported
 F:	arch/arm64/boot/dts/amd/amd-seattle-xgbe*.dtsi