Fix Todo: remove comment flush ex

Created by: silabs-PaulZ

Fixes two TODOs in the cv32e40p_controller.sv RTL based on issue #430 (closed)

The comment is not clear. The code is written correctly whereby an illegal instruction or ecall instruction will enter the FLUSH_EX state while running in single-step mode. @bluewww , Can you please review this PR as you may have entered this TODO comment on a previous change: https://github.com/openhwgroup/cv32e40p/commit/efc02fc77cf250d3c2c618ae406ca6cbe0689e7e#diff-f8105fd1c66cefe40c50f701d9f3108eR565

Signed-off-by: Paul Zavalney paul.zavalney@silabs.com