nimble/ll: Fix HCI events order on slave connection
nimble/ll: Fix HCI events order on slave connection

If a connection is created and the Controller supports the LE Channel
Selection Algorithm #2 feature, this event shall be immediately
followed by an LE Channel Selection Algorithm Event.

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