ASoC: palm27x: Automatically disconnect non-connected pins

All DAPM input and output pins of the wm9712 are either used in the card's
DAPM routing table or are marked as not connected.

Set the fully_routed flag of the card instead of manually marking the unused
inputs and outputs as not connected. This makes the code a bit shorter and
cleaner.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>