shippable: add ppc64el targets

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

.shippable.yml

@@ -16,6 +16,8 @@ env:
     # mips64el-softmmu disabled due to libfdt problem
     - IMAGE=debian-mipsel-cross
       TARGET_LIST=mipsel-softmmu,mipsel-linux-user,mips64el-linux-user
+    - IMAGE=debian-ppc64el-cross
+      TARGET_LIST=ppc64-softmmu,ppc64-linux-user,ppc64abi32-linux-user
 build:
   pre_ci:
     - make docker-image-${IMAGE} V=1