ath9k_htc: do some initial hardware configuration

Currently we configure harwdare and clock, only after
interface start. In this case, if we reload module or
reboot PC without configuring adapter, firmware will freeze.
There is no software way to reset adpter.

This patch add initial configuration and set it in
disabled state, to avoid this freeze. Behaviour of this patch
should be similar to: ifconfig wlan0 up; ifconfig wlan0 down.

Bug: https://github.com/qca/open-ath9k-htc-firmware/issues/1


Tested-by: Bo Shi <cnshibo@gmail.com>
Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>