ARM: dts: apq8064: add i2c sleep pinctrl states.

This patch adds missing i2c pinctrl sleep states.
Also add 16mA drive strength to the pins so that we can detect wide
range of i2c devices on the other side of level shifters.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>