ARM: OMAP3: cpuidle - remove the 'valid' field

ARM: OMAP3: cpuidle - remove the 'valid' field

With the previous changes all the states are valid, except the last
state which is now handled at runtime by next_valid_state() based on
the errata flags.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
[khilman@ti.com: minor changelog rework]
Signed-off-by: Kevin Hilman <khilman@ti.com>