permanent disabling of Wireless-N for Thinkpad

[Haines Brown <haines@histomat.net>]

I'm running Jessie on a x250 Thinkpad and encountered the common problem
of its dropping its wifi connection. The fix was to disable the
Wireless-N function of the iwlwifi module when I load it.

I want to make this permanent, which I gather can be done by placing the
line 11n_disable=1 into /etc/modprobe.d/wireless.conf. However, such a
file does not appear in my Jessie. Can it be created and simply hold the
line above? Or should I add the line options 11n_disable=1 to the
/etc/modprobe.d/modesetting.conf file? Or should I create a iwlwifi.conf
file?

Haines Brown