kernel: ltq-vectoring: add patch fixing compilation warning

kernel: ltq-vectoring: add patch fixing compilation warning

Add patch fixing compilation warning related to stack limit.
Fix compilation warning:
/builder/shared-workdir/build/build_dir/target-mips_24kc_musl/linux-lantiq_xrx200/ltq-vectoring-2019-05-20-4fa7ac30/src/vectoring/ifxmips_vectoring.c: In function 'proc_write_dbg':
/builder/shared-workdir/build/build_dir/target-mips_24kc_musl/linux-lantiq_xrx200/ltq-vectoring-2019-05-20-4fa7ac30/src/vectoring/ifxmips_vectoring.c:369:1: error: the frame size of 2088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
  369 | }
      | ^
cc1: all warnings being treated as errors

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>