ASoC: wm8985: Remove unused pointer in wm8985_remove()

Commit a0b148b4 (ASoC: wm8985: Use devm_regulator_bulk_get()) removed the last
user of pointer wm8985 to struct wm8985_priv. Thus remove it. Detected by
Coverity CID 1222150.

Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>