MAINTAINERS: Update AMD XGBE driver maintainers

Due to other additional responsibilities Tom would no longer
be able to support AMD XGBE driver.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20230116085015.443127-1-Shyam-sundar.S-k@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>