ARM: dts: omap4-panda: Add pinmux configuration for HDMI

Add the pinmux configuration for HDMI and TPD12S015A. Configure the
gpios for the TPD12S015A and SDA, SCL and CEC for HDMI.

Signed-off-by: Ricardo Neri <ricardo.neri@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>