MIPS: Remove duplicated include from numa.c

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7537/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>