Bluetooth: controller: Add double buffer for DF sync configuration

CTE sampling enable or disable requests should be provided to LLL.
Double buffer of lll_df_sync_cfg is added to lll_sync for that purpose
Thanks to that:
- there is no need to synchronize LLL with LL thread
- LLL has always access to valid configuration (new or former)

The configuration is stored in double buffer as instances
of lll_df_sync_cfg, not as pointers. This is the only
difference between double buffer pattern used to store adverising PDU.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>
4 files changed