travis: add ppc64le builds.

Change-Id: I4c85084bb4e54c521889d4549718ea5ecf24481b
Reviewed-on: https://code.wireshark.org/review/35081
Reviewed-by: Anders Broman <a.broman58@gmail.com>

.travis.yml

@@ -50,6 +50,11 @@ matrix:
       arch: s390x
       env:
         - PCAP=ON
+    - name: Linux ppc64le (gcc-7) with PCAP
+      os: linux
+      arch: ppc64le
+      env:
+        - PCAP=ON
     - name: Linux (gcc-8) without PCAP
       os: linux
       addons:
@@ -82,6 +87,13 @@ matrix:
         - CXX=clang++
         - CC=clang
         - PCAP=ON
+    - name: Linux ppc64le (clang) with PCAP
+      os: linux
+      arch: ppc64le
+      env:
+        - CXX=clang++
+        - CC=clang
+        - PCAP=ON
     - name: Linux (clang) without PCAP
       os: linux
       env: