qcacmn: check for in use flag during free

Add a in_use flag to identify if a rx desc is associated
with a valid nbuf and use this flag while freeing the nbuf.

Change-Id: Iace002ecadfd95ce60b7d1eaebc42194a433963b
CRs-fixed: 2044907

dp/wifi3.0/dp_rx.h

@@ -70,6 +70,7 @@ struct dp_rx_desc {
 #ifdef RX_DESC_DEBUG_CHECK
 	uint32_t magic;
 #endif
+	uint8_t in_use:1;
 };
 
 #define RX_DESC_COOKIE_INDEX_SHIFT		0
@@ -322,6 +323,7 @@ void dp_rx_add_to_free_desc_list(union dp_rx_desc_list_elem_t **head,
 	qdf_assert(head && new);
 
 	new->nbuf = NULL;
+	new->in_use = 0;
 
 	((union dp_rx_desc_list_elem_t *)new)->next = *head;
 	*head = (union dp_rx_desc_list_elem_t *)new;