misc: Move panel driver out of staging

Move panel driver from drivers/staging/panel to drivers/misc.

Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>