Blackfin char driver for Blackfin on-chip OTP memory (v3)

initial char driver for otp memory
(only read supported atm ... needs real examples/docs for write support)

v2-v3:
 - fixup __initdata with __initconst, as we are heading for 2.6.26

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Acked-by: Jiri Slaby <jirislaby@gmail.com>