.travis.yml: enable aarch64-softmmu and alpha-softmmu tcg tests

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

.travis.yml

@@ -284,5 +284,5 @@ matrix:
 
     # Run check-tcg against softmmu targets
     - env:
-        - CONFIG="--target-list=xtensa-softmmu,arm-softmmu"
+        - CONFIG="--target-list=xtensa-softmmu,arm-softmmu,aarch64-softmmu,alpha-softmmu"
         - TEST_CMD="make -j3 check-tcg V=1"