dt-bindings: arm: idle-states: Use "e.g." and "i.e." consistently

Replace abbreviations "eg" and "ie" by "e.g." resp. "i.e." for
consistency.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>