Bluetooth: controller: Support BT 5.0 feature set bit fields

Added support in the Controller for increased feature set
bit fields in Bluetooth 5.0. Cached feature set in the
connection context is increased to a uint32_t value to
accommodate 17 feature bits.

Change-id: I9ae15d6d90fa7a3de186905d3c68088ee22d2911
Signed-off-by: Vinayak Chettimada <vinayak.kariappa.chettimada@nordicsemi.no>