Bluetooth: controller: Fix for CPR with/without Feature Exchange

Fix implementation to support Connection Parameter Request
Procedure initiation with and without use of Feature
Exchange Procedure being performed in a connection.

Fixes LL.TS.5.0.2 conformance tests:
LL/CON/MAS/BV-81-C [Initiating Connection Parameter Request
                    - Unsupported Without Feature Exchange]
LL/CON/MAS/BV-82-C [Initiating Connection Parameter Request
                    - Unsupported With Feature Exchange]
LL/CON/SLA/BV-85-C [Initiating Connection Parameter Request
                    - Unsupported Without Feature Exchange]
LL/CON/SLA/BV-86-C [Initiating Connection Parameter Request
                    - Unsupported With Feature Exchange]

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>