panel: s6e3hc3: throttle auto mode when idle_delay is set

Auto mode gets re-triggered every time there is a new commit. In order
to prevent refresh rate updates from happening too often (based on
"idle_delay_ms" sysfs node), delay auto mode re-triggering when the
delay is set. This leads to switching to manual mode refresh rate
update, and hibernation (via set_self_refresh call) will make it switch
back to auto mode.

Bug: 203002561
Signed-off-by: Adrian Salido <salidoa@google.com>
Change-Id: I899fa2a93a5e0c9f68174b885d553a5b8efac63b