Bluetooth: controller: Fix rejected enc procedure not terminated

Fix issue in the handling of LL_REJECT_EXT_IND packets, this would look
at the procedures that are enqueued, and not the procedure that was
being rejected. This meant that although a reject was received for the
encryption procedure, the handling for a different control procedure was
run.
This would result in the link being terminated as control procedure
timer would time out for the encryption procedure.

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>