nimble/ll: Run RPA timer when resolving list is used
nimble/ll: Run RPA timer when resolving list is used

This timer is use for RPA generation and is not related to address
resolution enable state. If there is something on RL we keep timer
running.

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