[FOR STABLE] wireless: Skip directory when generating certificates

Hello stable!

I'd like to see the following commit included in -stable trees:

commit 32b5a2c9950b9284000059d752f7afa164deb15e Author: Maxim Mikityanskiy maxtram95@gmail.com Date: Tue May 7 20:28:15 2019 +0300

wireless: Skip directory when generating certificates

As it is, CONFIG_CFG80211_EXTRA_REGDB_KEYDIR is broken between v4.15 and v5.2.

Thanks, Brian

P.S. I've take the "Option 2" in Documentation/process/stable-kernel-rules.rst. Let me know if I should do differently.