According to Shell spec 2.2 '-exit' invocation option is used to specify
that after running the command line when launched, the UEFI Shell must
immediately exit.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chen A Chen <chen.a.chen@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>