arm64: dts: qcom: sc7180: Start the trogdor eDP/touchscreen regulator on

Now that we've added the `off-on-delay-us` for the touchpanel
regulator, we can see that we're actually hitting that delay at
bootup. I saw about 200 ms of delay.

Let's avoid that delay by starting the regulator on. We'll only do
this for eDP devices for the time being.

NOTE: we _won't_ do this for homestar. Homestar's panel really likes
to be power cycled. It's why the Linux driver for this panel has a
pm_runtime_put_sync_suspend() when the panel is being unprepared but
the normal panel-edp driver doesn't. It's also why this hardware has a
separate power rail for eDP vs. touchscreen, unlike all the other
trogdor boards. We won't start homestar's regulator on. While this
could mean a slight delay on homestar, it is probably a _correct_
delay. The bootloader might have left the regulator on (it does so in
dev and recovery modes), so if we turned the regulator off at probe
time and we actually hit the delay then we were probably violating T12
in the panel spec.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221209091234.v3.3.I7050a61ba3a48e44b86053f265265b5e3c0cee31@changeid