powerpc: Fix memory leak in axon_msi.c

cppcheck found a memory leak in axon_msi, if dcr_base or dcr_len are zero,
we have already allocated msic, so we should free it in the error path.

Signed-off-by: Eric Sesterhenn <eric.sesterhenn@lsexperts.de>
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/cell/axon_msi.c

@@ -365,7 +365,7 @@ static int axon_msi_probe(struct of_device *device,
 		printk(KERN_ERR
 		       "axon_msi: couldn't parse dcr properties on %s\n",
 			dn->full_name);
-		goto out;
+		goto out_free_msic;
 	}
 
 	msic->dcr_host = dcr_map(dn, dcr_base, dcr_len);