submarine: Stop timers on water filling & flushing

Currently, the Timer runs depending on the values of waterFilling and
waterFlushing. However, both of them will keep on updating when both of
the vaults are turned on, in which case water inflow = water outflow
and updating the water level is unnecessary

Signed-off-by: Rudra Nil Basu <rudra.nil.basu.1996@gmail.com>