backports: add a 120 second timeout rule to Coccinelle

backports: add a 120 second timeout rule to Coccinelle

Our current overall run time is less than 120 seconds so lets
add a trigger to fail if we have a rule taking longer. Adding
this has no extra incurred overhead cost.

mcgrof@drvbp1 ~/backports (git::master)$ time ./gentree.py --clean
/home/mcgrof/linux-next /home/mcgrof/build/next-20140411
Copy original source files ...
Apply patches ...
Modify Kconfig tree ...
Rewrite Makefiles and Kconfig files ...
Done!

real    1m15.463s
user    10m49.100s
sys     0m37.100s

Cc: Peter Senna <peter.senna@gmail.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Gilles Muller <Gilles.Muller@lip6.fr>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>