nand-fifo: Add byte counter output

This tells how many bytes were read since a reset.
kovan-sd: Hook up byte_counter register

This takes advantage of the new byte_counter NAND register.
ucf: Re-order NAND data pins

The pins need to be swapped around, but a re-order is the first step.
nand-fifo: Fix race condition for data reading

Sometimes the data wouldn't get properly read.  This was due to
very long buffer times coming from the read side.  We eliminate
one clock cycle, and things are good now.