dt-bindings: input: Fix the keymap for LOCK key

Decouple LOCK from F13 and directly map the LOCK key (KSI3/KSO9) to
KEY_SLEEP action key code.

Signed-off-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210115143555.v6.3.I96134907488f41f358d03f3c1b08194f9547e670@changeid


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>