Remove vdin, we ignore output under reset anyway.
Reword encode module inputs/outputs to make them more friendly.
Apply some standard/dual basis naming
Simplify dpdbm slightly
Simplify dpdbm further
Rename dpdbm to parallel_mixed_multiplier
Rework and rename dsdbmRing to serial_mexd_multiplier

Its opencoded in tmec_decode_serial, roll it into a single module
to make it more clear what exactly is going on (lfsr being shared)
Rework dpm and rename to parallel_standard_multiplier

Save on conversion to dual basis by allowing conversion to be reused
across multiple inputs.
Rename dssbm to serial_standard_multiplier
Simplify parallel_standard_multiplier usage in tmec parallel by reusing dr
Shorten bNout assignment slightly
Simplify cNout assignment
Simplify cNin assignment
re-org tmec_decode_parallel a bit
Simplify mul1 for cases where the argument is not a constant
Fix a couple of syntatical typos in bch_math
Greatly simplify parallel_standard_multiplier

This makes it much clearer what is being done
Comment serial_standard_multiplier a bit