tf-a-builder: match defaut branch/refspec to master

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: I8229b651450667927143ac7ac1b4bf62223e2a71
diff --git a/tf-a-builder.yaml b/tf-a-builder.yaml
index af011a3..f19aded 100644
--- a/tf-a-builder.yaml
+++ b/tf-a-builder.yaml
@@ -54,7 +54,7 @@
             default: 'TF-A/trusted-firmware-a'
         - string:
             name: GERRIT_BRANCH
-            default: 'integration'
+            default: 'master'
         - string:
             name: GERRIT_REFSPEC
             default: 'refs/heads/master'