maintainers: update for NTB
maintainers: update for NTB

Remove Xiaoyun and add Junfeng.

Signed-off-by: Junfeng Guo <4e83c95a099a2e36f95a0baa7b159dfaca2b98e9@intel.com>
Acked-by: Xiaoyun Li <151cc00bdba86cfa2ecfc39aaa98def8f092d9d8@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk