ninja: WP signal is used as open-drain

The hardware design of the WP signal from servo is used as open-drain.
There are some PU by 3.3V and then it is shifted to 1.8V through FET's.
So don't need to supply any voltage; otherwise, it conflicts with the
SPI voltage, which is actually 1.8V.

BUG=b:116049278
TEST=dut-control fw_wp_state:force_off; Checked EC GPIO WP_L is 1.
TEST=dut-control fw_wp_state:force_on; Checked EC GPIO WP_L is 0.
TEST=USB works fine no matter fw_wp_state is force_on or force_off.

Change-Id: I4a5a4a96e71056bbacc040e2808eb59ceb506b74
Signed-off-by: Wai-Hong Tam <waihong@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1321165
Reviewed-by: Kevin Shelton <kmshelton@chromium.org>
Reviewed-by: YH Lin <yueherngl@chromium.org>
1 file changed