ASoC: pxa: add I2C dependencies as needed

We have in the past added 'depends on I2C' for some of the PXA boards
after hitting randconfig build bugs. I have seens a couple of new
bugs in this area during the linux-next cycle for 3.16, after it
became possible to build some more PXA machines with I2C disabled.

To shut this up for good, this adds the dependency to every board
that uses I2C as the interface to the codec. I have gone through
all board files and verified that they all either use AC97 or
I2C, and this annotates the latter. Some of these already enable
I2C from mach-pxa/Kconfig, but since that can change it's better
to be explicit here.

The link error that can result otherwise happens when CONFIG_I2C
is set to 'm' and the codec driver is built-in as a result of being
selected by the platform specific glue.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@linaro.org>