blackfin: rename bfin-twi_i2c driver to adi_i2c

drivers/i2c/Makefile

drivers/i2c/adi_i2c.c

include/configs/bct-brettl2.h

include/configs/bf518f-ezbrd.h

include/configs/bf526-ezbrd.h

include/configs/bf527-ad7160-eval.h

include/configs/bf527-ezkit.h

include/configs/bf527-sdp.h

include/configs/bf537-minotaur.h

include/configs/bf537-pnav.h

include/configs/bf537-srv1.h

include/configs/bf537-stamp.h

include/configs/bf538f-ezkit.h

include/configs/bf548-ezkit.h

include/configs/bf609-ezkit.h

include/configs/br4.h

include/configs/cm-bf527.h

include/configs/cm-bf537e.h

include/configs/cm-bf537u.h

include/configs/cm-bf548.h