superio/ite/it8728f: Hook up common environment-controller driver

This replaces the custom environment controller handling in the it8728
driver with the common library.

It also updates the two existing boards with hwm register settings in
their devicetree config so they better match their vendor BIOS fan
control settings.

Change-Id: Idf0c8908ba5ad6ff552b8302bffc638aa9052941
Signed-off-by: Tobias Diedrich <ranma+coreboot@tdiedrich.de>
Reviewed-on: https://review.coreboot.org/19293
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
7 files changed