MIPS: APRP: Fix the linking of rtlx interrupt hook

There are 2 errors with the existing aprp_hook linking:
- The prefix CONFIG_ is missing;
- The hook should be linked exclusively in the cases of MT and CMP.
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: john@phrozen.org
Patchwork: https://patchwork.linux-mips.org/patch/6588/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>