gitlab-ci: Replace aarch64 with arm in cross-i686-tci build

Configuration of 64-bit host on 32-bit guest will shortly
be denied.  Use a 32-bit guest instead.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

.gitlab-ci.d/crossbuilds.yml

@@ -61,7 +61,7 @@ cross-i686-tci:
   variables:
     IMAGE: debian-i686-cross
     ACCEL: tcg-interpreter
-    EXTRA_CONFIGURE_OPTS: --target-list=i386-softmmu,i386-linux-user,aarch64-softmmu,aarch64-linux-user,ppc-softmmu,ppc-linux-user --disable-plugins --disable-kvm
+    EXTRA_CONFIGURE_OPTS: --target-list=i386-softmmu,i386-linux-user,arm-softmmu,arm-linux-user,ppc-softmmu,ppc-linux-user --disable-plugins --disable-kvm
     # Force tests to run with reduced parallelism, to see whether this
     # reduces the flakiness of this CI job. The CI
     # environment by default shows us 8 CPUs and so we