configure: remove unnecessary mkdir -p

It is already included in the symlink shell function.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -1775,7 +1775,6 @@ fi
 for target in $target_list; do
     target_dir="$target"
     target_name=$(echo $target | cut -d '-' -f 1)$EXESUF
-    mkdir -p "$target_dir"
     case $target in
         *-user) symlink "../qemu-$target_name" "$target_dir/qemu-$target_name" ;;
         *) symlink "../qemu-system-$target_name" "$target_dir/qemu-system-$target_name" ;;