ASoC: apq8016-sbc: dt bindings: remove incorrect property

This patch removes capture-dai property which should not have existed
in this document in the first place. It looks like leftover from old
version of patches by mistake.

Remove it to avoid any confusion in future.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>