firewire: core: do not DMA-map stack addresses

The DMA mapping API cannot map on-stack addresses, as explained in
Documentation/DMA-mapping.txt.  Convert the two cases of on-stack packet
payload buffers in firewire-core (payload of lock requests in the bus
manager work and in iso resource management) to slab-allocated memory.

There are a number on-stack buffers for quadlet write or quadlet read
requests in firewire-core and firewire-sbp2.  These are harmless; they
are copied to/ from card driver internal DMA buffers since quadlet
payloads are inlined with packet headers.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index 9823946..192d1e43 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -127,6 +127,7 @@
 	struct delayed_work work;
 	int bm_retries;
 	int bm_generation;
+	__be32 bm_transaction_data[2];
 
 	bool broadcast_channel_allocated;
 	u32 broadcast_channel;