elm: anx7688: make anx7688 always on
elm: anx7688: make anx7688 always on

This makes the boot time less painful since it requires a long delay
for FW loading after power on this chip. This also makes it easier to
upgrade FW as we don't need to power on the chip before doing upgrade.

BRANCH=none
BUG=chrome-os-partner:52815
TEST=plug and unplug dongle and check DP output
     plug/unplug adapter and check pd 0 state

Change-Id: Ia344c748697a3b1d06c9b442e1bf1d7227861f9b
Signed-off-by: Tang Zhentian1 <a1269c0df3bffcdec7b2711cfcc3364aa631ef3d@analogixsemi.com>
Signed-off-by: Koro Chen <a316d89c8b5185b78cc2c56b469d422d2a73588f@mediatek.com>
Reviewed-on: https://chromium-review.googlesource.com/347181
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec