Fix the comments on the precision of quantizers and tx coefficients
during a quantization process for different input depth and tx size.

I think the author really meant "de-quantized/de-coded coefficients" by
"quantized/coded coefficients". So, made it clear to avoid any possible
misunderstandings.

Change-Id: Ib92ac7dcfddcbe58cf3adfb9448497512381c1f5