nimble/host: Allow setting adv data when advertising
nimble/host: Allow setting adv data when advertising

Not sure why this was not allowed, but it is perfectly ok to do so and
controller will update data while advertising. And even if for some
reason it won't, there will be proper error returned.

X-Original-Commit: 103638b5e98cfabf59fc1ac646c71840071ec22a

apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble