Add simple .travis.yml

This adds the .travis.yml file allowing for dtc building and testing in
the Travis Continuous Integration system.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

.travis.yml

diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..f2336d8
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,5 @@
+language: c
+
+script:
+        - make
+        - make check