wcn36xx: reduce verbosity of drivers messages

Whenever the WLAN interface is started the FW
version and caps are printed.
The caps now will be displayed only in debug mode.
Firmware version will be displayed only once on first
startup of the interface.

Change-Id: I4db6ea7f384fe15eebe4c3ddb1d1ccab00094332
Signed-off-by: Ramon Fried <rfried@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>