ASoC: wm8804: Merge CODEC probe and bus probe

All of the things in the CODEC probe, such as getting the regulators and
verifying the chip ID, are better done in bus probe. It is better to
fail during bus probe if this is the wrong chip and all resource
allocation should be done in the bus probe anyway. This patch merges
the CODEC probe into bus probe.

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