OMAPDSS: change signal_level & signal_edge enum values

At the moment the enum values for ACTIVE_HIGH and RISING_EDGE are 0, and
ACTIVE_LOW and FALLING_EDGE are 1, to match the values programmed to HW.
The previous patch removed this dependency.

Swap the enum values the other way around. This doesn't change the
behavior in any way, but makes it easier to debug as value of '1' means
HIGH or RISING.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>