Missing ';' in the end of secure-monitor example node.

Fixes: 165b5fb2 ("dt-bindings: power: add Amlogic secure power domains bindings")
Reported-by: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/1583164448-83438-1-git-send-email-jianxin.pan@amlogic.com