MAINTAINERS: Update AMD XGBE driver maintainers

Due to additional responsibilities, Shyam Sundar S K will no longer be
supporting the AMD XGBE driver. Maintenance will be handled by
Raju Rangoju going forward.

Cc: Raju Rangoju <Raju.Rangoju@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://patch.msgid.link/20260223074020.1987884-1-Shyam-sundar.S-k@amd.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>