clk: wm831x: get rid of the implementation of remove function

The remove function implemented for platform driver's remove callback
just return 0 as part of its implementation.

Remove this APIs and do not pass the valid .remove for platform driver.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>