[nrf fromtree] Bluetooth: Controller: Fix assertion due to late PER CIS active set

Fix assertion due to late Peripheral CIS active flag being
initialized. CIS active flag shall be initialized when it is
acquired.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
(cherry picked from commit cb28104)
Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>

Author: cvinayak

subsys/bluetooth/controller/ll_sw/ull_peripheral_iso.c

@@ -250,7 +250,8 @@ uint8_t ull_peripheral_iso_acquire(struct ll_conn *acl,
 	cis->p_max_sdu = (uint16_t)(req->p_max_sdu[1] & 0x0F) << 8 |
 				    req->p_max_sdu[0];
 
-	cis->lll.handle = 0xFFFF;
+	cis->lll.active = 0U;
+	cis->lll.handle = LLL_HANDLE_INVALID;
 	cis->lll.acl_handle = acl->lll.handle;
 	cis->lll.sub_interval = sys_get_le24(req->sub_interval);
 	cis->lll.nse = req->nse;
@@ -325,7 +326,6 @@ uint8_t ull_peripheral_iso_setup(struct pdu_data_llctrl_cis_ind *ind,
 	cis->lll.cie = 0U;
 	cis->lll.npi = 0U;
 	cis->lll.flush = LLL_CIS_FLUSH_NONE;
-	cis->lll.active = 0U;
 	cis->lll.datapath_ready_rx = 0U;
 	cis->lll.tx.payload_count = 0U;
 	cis->lll.rx.payload_count = 0U;