ARM: ux500: move AB8500 YCBCR settings to device tree

This moves the pin control settings for the YCBCR connector
on the AB8500 over to the device tree as a hog.

Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>