wifi: fill in MODULE_DESCRIPTION()s for wcn36xx

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Qualcomm Atheros WCN3660/3680 wireless driver.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240130104243.3025393-6-leitao@debian.org