ASoC: sun4i-codec: Enable bus clock after getting GPIO

In the current probe function the GPIO is acquired after the codec's
bus clock is enabled. However if it fails to acquire the GPIO due to
a deferred probe, it does not disable the bus clock before bailing out.
This would result in the clock being enabled multiple times.

Move the code that enables the bus clock after the part that gets the
GPIO, maintaining a separation between resource acquisition and device
enablement in the probe function.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>