firewire: fw-ohci: shut up false compiler warning on PPC32

Shut up "may be used uninitialised in this function" warnings due to
PPC32's implementation of dma_alloc_coherent().
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/fw-ohci.c

@@ -281,7 +281,7 @@ static int ar_context_add_page(struct ar_context *ctx)
 {
 	struct device *dev = ctx->ohci->card.device;
 	struct ar_buffer *ab;
-	dma_addr_t ab_bus;
+	dma_addr_t uninitialized_var(ab_bus);
 	size_t offset;
 
 	ab = dma_alloc_coherent(dev, PAGE_SIZE, &ab_bus, GFP_ATOMIC);
@@ -536,7 +536,7 @@ static int
 context_add_buffer(struct context *ctx)
 {
 	struct descriptor_buffer *desc;
-	dma_addr_t bus_addr;
+	dma_addr_t uninitialized_var(bus_addr);
 	int offset;
 
 	/*
@@ -1321,7 +1321,7 @@ ohci_set_config_rom(struct fw_card *card, u32 *config_rom, size_t length)
 	unsigned long flags;
 	int retval = -EBUSY;
 	__be32 *next_config_rom;
-	dma_addr_t next_config_rom_bus;
+	dma_addr_t uninitialized_var(next_config_rom_bus);
 
 	ohci = fw_ohci(card);