MdeModulePkg: Remove superfluous return statements
    
    If the code eventually returns "Status" anyway, it does not make
    sense to explicitly return "Status" in case of an error, too.
    
    Contributed-under: TianoCore Contribution Agreement 1.0
    Signed-off-by: Thomas Huth <thuth@redhat.com>
    Reviewed-by: Star Zeng <star.zeng@intel.com>