travis: Enable travis CI for ppc64le arch

Enable travis CI for ppc64le arch

Signed-off-by: Nitesh Konkar <niteshkonkar@in.ibm.com>

.travis.yml

@@ -6,12 +6,12 @@ services:
 
 language: go
 
+os:
+- linux
+- linux-ppc64le
+
 go:
   - "1.12.x"
-os:
-  - "linux"
-  # TODO ppc64le is currently timing out on travis; see https://github.com/containerd/containerd/pull/2896
-  # - "linux-ppc64le"
 
 matrix:
   include:
@@ -41,6 +41,11 @@ env:
   - TRAVIS_GOOS=linux TEST_RUNTIME=io.containerd.runc.v2 TRAVIS_CGO_ENABLED=1
   - TRAVIS_GOOS=linux TEST_RUNTIME=io.containerd.runtime.v1.linux TRAVIS_CGO_ENABLED=1
 
+matrix:
+    exclude:
+       - env: TRAVIS_GOOS=darwin TRAVIS_CGO_ENABLED=0
+         os: linux-ppc64le
+
 before_install:
   - uname -r