examples/wakaama: remove useless BOARD_BLACKLIST
examples/wakaama: remove useless BOARD_BLACKLIST

The wakaama examples now builds fine on pic32 boards

authmillenon/RIOT,mtausig/RIOT,jasonatran/RIOT,basilfx/RIOT,toonst/RIOT,mtausig/RIOT,kaspar030/RIOT,yogo1212/RIOT,x3ro/RIOT,mtausig/RIOT,kaspar030/RIOT,miri64/RIOT,OlegHahm/RIOT,jasonatran/RIOT,kYc0o/RIOT,mtausig/RIOT,toonst/RIOT,basilfx/RIOT,kaspar030/RIOT,ant9000/RIOT,mtausig/RIOT,toonst/RIOT,josephnoir/RIOT,yogo1212/RIOT,x3ro/RIOT,jasonatran/RIOT,ant9000/RIOT,aeneby/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,toonst/RIOT,OTAkeys/RIOT,aeneby/RIOT,toonst/RIOT,smlng/RIOT,yogo1212/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,authmillenon/RIOT,yogo1212/RIOT,aeneby/RIOT,aeneby/RIOT,authmillenon/RIOT,smlng/RIOT,x3ro/RIOT,miri64/RIOT,josephnoir/RIOT,kaspar030/RIOT,kYc0o/RIOT,yogo1212/RIOT,OTAkeys/RIOT,jasonatran/RIOT,kYc0o/RIOT,OTAkeys/RIOT,smlng/RIOT,josephnoir/RIOT,authmillenon/RIOT,jasonatran/RIOT,basilfx/RIOT,OlegHahm/RIOT,yogo1212/RIOT,authmillenon/RIOT,aeneby/RIOT,ant9000/RIOT,x3ro/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,authmillenon/RIOT,ant9000/RIOT,miri64/RIOT,kaspar030/RIOT,miri64/RIOT,smlng/RIOT,RIOT-OS/RIOT,basilfx/RIOT,josephnoir/RIOT,smlng/RIOT,kYc0o/RIOT,ant9000/RIOT,basilfx/RIOT,x3ro/RIOT,miri64/RIOT,OTAkeys/RIOT,josephnoir/RIOT