* smart_gpio.cpp: check _add return values
And occupy gpiochip's pin range if disabled of failed. So base will
align with enum.
* TLE8888: cleanup, move high level code to smart_gpio.cpp
* smart_gpio.cpp: fix compilation when BOARD_EXT_GPIOCHIPS == 0
* board-subaru: fix compilation after latest smart_gpio updates
* tle8888: now we have all 28 pins supported