ARM: ux500: move AB8500 PWM out settings to device tree

This moves the muxing and biasing of the AB8500 PWM output pins
over to the device tree for affected platforms.

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