Tidy up c2k_otp.h and mach/otp.h files

We had accidentally ended up with two files that defined the otp_write and
otp_read functions. Instead, put the prototypes in c2k_otp.h, and implementation
details in mach/otp.h

Change-Id: I768dccb86686acec7aab9d39164867db943389f2
4 files changed