nimble/ll: Fix setting sent_to_host flag
nimble/ll: Fix setting sent_to_host flag

There's no point in setting flag only to clear it in a moment - just
make sure we don't set it when not needed.

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