ARM: ux500: Ensure probing of Audio devices when Device Tree is enabled

Previous attempts to add platform probing of the Audio related devices
only call from non-DT initialisation functions. This patch extends that
functionality to the Device Tree related ones too.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>