Bump LTP timeout to 3h

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
diff --git a/lava-submit.py b/lava-submit.py
index b700819..fb62726 100755
--- a/lava-submit.py
+++ b/lava-submit.py
@@ -17,7 +17,7 @@
     'gatortests': 1200,
     'kernel-version': 800,
     'leb-basic-graphics': 7200,
-    'ltp': 7200,
+    'ltp': 10800,
     'mysql': 800,
     'network-tests-basic': 1200,
     'perf': 800,