ARM: versatile: enable the right LEDs

The Versatile now only has device tree boot support, and the
device tree version does not support CONFIG_LEDS_VERSATILE.
Instead select CONFIG_LEDS_SYSCON and MFD_SYSCON, so we can
get LEDs support from the same generic driver that drives
most other ARM reference boards.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>