ARM: ux500: Fix initialisation order for UIBs

An earlier change prevented User Interface Boards (UIBs) from being
initialised on boards which did not support them. This change had
the undesired effect of reordering the UIB initialisation calls with
I2C registration. Here we ensure UIBs are only setup after all
required infrastructure is already in place.

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