fbdev/core: Pass Linux device to pm_vt_switch_*() functions

Pass the Linux device to pm_vt_switch_*() instead of the virtual
fbdev device. Prepares fbdev for making struct fb_info.dev optional.

The type of device that is passed to the PM functions does not matter
much. It is only a token within the internal list of known devices.
The PM functions do not refer to any of the device's properties or its
type.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-pm@vger.kernel.org
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-33-tzimmermann@suse.de