[PATCH] Default to an ARM cpu that exists

[coypu]

Regarding target/86383, it wasn't sufficient to not just pick arm6 for
netbsd, as the default -mcpu is still arm6, which also fails to build.

I assume the default is expected to be the oldest support, and I think
now that's arm8, so maybe default to that.

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 720e6a737..278c48287 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -3987,7 +3987,7 @@ case "${target}" in
                                TM_MULTILIB_CONFIG="$with_multilib_list"
                        fi
                fi
-               target_cpu_cname=${target_cpu_cname:-arm6}
+               target_cpu_cname=${target_cpu_cname:-arm8}
                with_cpu=${with_cpu:-$target_cpu_cname}
                ;;