Bluetooth: Controller: df: Fix missing disable CTE req LLCP after compl

The CTE request procedure can be run in periodic and non-periodic mode.
In periodic mode it stays enabled until Host call HCI_LE_Connection_CTE-
_Request_Enable(Enable=0x0).
In non-periodic mode the command is disabled after completion,
LL_CTE_RSP is successfully received.

There is missing disable of the procedure in the current code,
so Host is not able to run the command HCI_LE_Connection_CTE_Request_-
Enable(Enable=0x1) again without explicit call to HCI_LE_Connection_-
CTE_Request_Enable(Enable=0x0).

The commit adds missing code responsible for disable of the procedure.

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