verilog: Fixing usage of cell reserved word.

`cell` is a Verilog reserved word.

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>
tree: 54c27556d89619328f81c59fed7cfd057c4ed41c
  1. cells/
  2. models/
  3. tech/
  4. timing/
  5. .gitignore
  6. LICENSE
  7. README.rst