ARM: 9463/1: Allow to enable RT

All known issues have been adressed.
Allow to select RT.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>