ASoC: arizona: Attach SYSCLK to DSP preloaders

Currently SYSCLK is attached to every compressed DAI as this follows the
pattern of attaching clocks to the chips inputs and outputs, however, it is
really the DSP that requires the clock here. As firmware download can be a
significant part of the path startup time for these devices occasionally it
would be desirable to download the firmware in advance of the path being
brought up.

To help facilitate this early firmware loading this patch attaches the
SYSCLK to the DSP preloader widget. This also saves us adding a new route
to SYSCLK every time a new compressed DAI is created.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>