Bluetooth: Controller: Fix nRF CCM disable on connection event abort

Fix missing nRF CCM disable on connection event abort.

There can be a problem on nRF SoC for example when a S8
"encrypted" reception is aborted, and a 2M "cleartext"
reception starts; slow CCM (that is not stopped as part of
radio disable) will corrupt a fast received "cleartext" when
the same current free rx buffer is reused in the Controller.
This is not a problem when the connection being abort-ee is
on a faster PHY than the abort-er.

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