Bluetooth: controller: Fix incorrect prev periodic header flag access

Fix Periodic Advertising PDU population from incorrectly
populating new PDU when there is no common extended header
flags being set in the previous PDU and or the new PDU.

Signed-off-by: Vinayak Kariappa Chettimada <[email protected]>

Author: cvinayak

subsys/bluetooth/controller/ll_sw/ull_adv_sync.c

@@ -672,7 +672,11 @@ static uint8_t adv_sync_hdr_set_clear(struct lll_adv_sync *lll_sync,
 	/* Get common pointers from reference to previous tertiary PDU data */
 	ter_com_hdr_prev = (void *)&ter_pdu_prev->adv_ext_ind;
 	ter_hdr = (void *)ter_com_hdr_prev->ext_hdr_adv_data;
-	ter_hdr_prev = *ter_hdr;
+	if (ter_com_hdr_prev->ext_hdr_len) {
+		ter_hdr_prev = *ter_hdr;
+	} else {
+		*(uint8_t *)&ter_hdr_prev = 0U;
+	}
 	ter_dptr_prev = ter_hdr->data;
 
 	/* Set common fields in reference to new tertiary PDU data buffer */