Travis: do both a Cortex-A build and a Cortex-M0+ build

The Cortex-A build is similar to Debian armel. The Cortex-M0+ is a
handy point of comparison for code size. Put that one last so that
it's easy to find in the log.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/.travis.yml b/.travis.yml
index a059ea8..c67c0cd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,8 +21,8 @@
       script:
         - tests/scripts/all.sh -k 'check_*'
         - tests/scripts/all.sh -k test_default_out_of_box
-        - tests/scripts/all.sh -k build_arm_none_eabi_gcc_arm5vte # baremetal
         - tests/scripts/test-ref-configs.pl
+        - tests/scripts/all.sh -k build_arm_none_eabi_gcc_arm5vte build_arm_none_eabi_gcc_m0plus
 
     - name: full configuration
       script: