faft: Wrap the underlying EC flash write protect command

This CL wraps the underlying flash write protect command into a method.
It makes the write protect more easy to be used without knowing any detail
of the EC command.

BUG=chromium-os:35254
TEST=run_remote_tests.sh --board link --remote dut ECWriteProtect/control$

Change-Id: If36345c5741ed7be9a962fba25fab25b4f2121e9
Reviewed-on: https://gerrit.chromium.org/gerrit/36867
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
2 files changed