ci-dockerfiles-sanity-check: increase timeout

The current timeout of one hour is not sufficient when making changes
that apply to all of the TF-A images - increase it to two hours.

Change-Id: Ide142dd99b75ec527e71a3d05939bd98e26c1e49
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/ci-dockerfiles-sanity-check.yaml b/ci-dockerfiles-sanity-check.yaml
index 0008a77..11611c0 100644
--- a/ci-dockerfiles-sanity-check.yaml
+++ b/ci-dockerfiles-sanity-check.yaml
@@ -68,7 +68,7 @@
     wrappers:
         - timestamps
         - timeout:
-            timeout: 60
+            timeout: 120
             fail: true
     builders:
         - shell: