OMAPDSS: HDMI5: Set valid sample order

As per TRM, HDMI_WP_AUDIO_CFG[2] LEFT_BEFORE = 0 is reserved,
so it must always be set to 1 (the first sample is the left).

Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>