v2 changes:
* Drop sw_blink_state structure, move its necessary fields to
led_uc_plat structure.
* Add cyclic_info pointer to led_uc_plat structure. This
simplify code a lot.
* Remove cyclic function search logic. Not needed anymore.
* Fix blinking period. It was twice large.
* Other cleanups.
v3 changes:
* Adapt code to recent cyclic function changes
* Move software blinking functions to separate file
* Other small changes
v4 changes:
* Refactoring of led_set_period() function
v5 changes
* Fix compilation if CONFIG_LED_BLINK is not defined
v6 changes:
* Enable LEDST_BLINK state unconditionally.
* Function led_set_period() becomes available when CONFIG_LED_BLINK
is disabled. This makes led code simpler.
* Software blinking requires about 100 bytes of data for a led. It's
not a good idea to allocate so much memory for each supported led.
Change the code to allocate blinking data only for required leds.