net: rfkill: gpio: remove unused and obsolete platform parameters

After upgrading to descriptor based gpios, the gpio numbers
are not used anymore. The power_clk_name and the platform
specific setup and close hooks are not used by anybody, and
we should not encourage use of such things, so removing them.

Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>