Kernel boot says:
bfin-gpio: GPIO 26 is already reserved by BFIN-GPIO! (Documentation/blackfin/bfin-gpio-notes.txt)
and
bfin-gpio: GPIO 21 is already reserved by BFIN-GPIO! (Documentation/blackfin/bfin-gpio-notes.txt)
which means GPIO 26 and 21 is already taken by some kind of device, try to to find out which devices they are and disable them directly if you don't need them, otherwise you may need to re-org your hardware. Let me know if you have issues when trying to do it.