Xceive 2028/3028 has a concept of scode/dcode.
Scode is a table of 16 values (each with 12 bytes i2c sequence).
Dcode is the entry of Scode table that should be used, given a certain
frequency.

The idea is that, depending on what frequency is selected, and according with a
country-based (or standard-based?) table, the Xceive should be "hacked" to
fine-tune that specific frequency.

By default, Scode=0 is used, for undefined frequencies. Also, Scode=0 seems to
be the most used value.

This patch adds the capability of selecting a scode. However, extra work will
be needed to allow auto-selecting the proper scode, for a given set of
frequencies.

I'm not sure what would be the proper way for implementing the dcode selection.
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>