toolchain: gcc: Backport patch to fix mips16 linking

toolchain: gcc: Backport patch to fix mips16 linking

Backport patch from upstream GCC 14 branch which fixes linking with
MIPS16 on the pistachio target.

This fixes the following link problem:
```
/builder/shared-workdir/build/staging_dir/toolchain-mipsel_24kc+24kf_gcc-14.2.0_musl/lib/gcc/mipsel-openwrt-linux-musl/14.2.0/../../../../mipsel-openwrt-linux-musl/bin/ld.bfd: ./liblua.so: undefined reference to `__mips16_ledf2'
/builder/shared-workdir/build/staging_dir/toolchain-mipsel_24kc+24kf_gcc-14.2.0_musl/lib/gcc/mipsel-openwrt-linux-musl/14.2.0/../../../../mipsel-openwrt-linux-musl/bin/ld.bfd: ./liblua.so: undefined reference to `__mips16_call_stub_df_2'
/builder/shared-workdir/build/staging_dir/toolchain-mipsel_24kc+24kf_gcc-14.2.0_musl/lib/gcc/mipsel-openwrt-linux-musl/14.2.0/../../../../mipsel-openwrt-linux-musl/bin/ld.bfd: ./liblua.so: undefined reference to `__mips16_muldf3'
```

Link: https://github.com/openwrt/openwrt/pull/18688
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>