ASoC: palm27x: register card in platform_driver probe

Remove creation of an soc-audio device from the machine platform_driver probe
function, and add a call to snd_soc_register_card() instead.

The current code still works, but this mechanism has been deprecated, if I'm not
mistaken.  The ASoC core code produces the warning "ASoC: machine Palm/PXA27x
should use snd_soc_register_card()"

Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>