Fix for issue #499.
Created by: silabs-oysteink
Horizontal traps (exceptions) to the same privilege level will now keep the value in mintstatus.mil stable. Previously this was updated to whatever value was on ctrl_fsm.irq_level regardless of exceptions or interrupts being taken.
Signed-off-by: Oystein Knauserud Oystein.Knauserud@silabs.com