turn_on_panel_on_resume is only used in toshiba_acpi.c now, change it
to static.

Fixes: 3cb1f40d ("drivers/platform: toshiba_acpi: Call HCI_PANEL_POWER_ON on resume on some models")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220920084434.3739493-1-yangyingliang@huawei.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>