fbdev: remove w90x900/nuc900 platform drivers

The ARM w90x900 platform is getting removed, so this driver is obsolete.

Link: https://lore.kernel.org/r/20190809202749.742267-10-arnd@arndb.de


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>