MIPS: Netlogic: Add XLP makefiles and config

- Add CPU_XLP and NLM_XLR_BOARD to arch/mips/Kconfig for Netlogic XLP boards
- Update mips Makefiles to add XLP

Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2968/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
7 files changed