etraxfs_eth: Don't use hw_error() in init() method

Device init() methods aren't supposed to call hw_error(), they should
report the error and fail cleanly.  Do that.

Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-Id: <1450370121-5768-5-git-send-email-armbru@redhat.com>

hw/net/etraxfs_eth.c

@@ -26,6 +26,7 @@
 #include "hw/sysbus.h"
 #include "net/net.h"
 #include "hw/cris/etraxfs.h"
+#include "qemu/error-report.h"
 
 #define D(x)
 
@@ -589,7 +590,8 @@ static int fs_eth_init(SysBusDevice *sbd)
     ETRAXFSEthState *s = ETRAX_FS_ETH(dev);
 
     if (!s->dma_out || !s->dma_in) {
-        hw_error("Unconnected ETRAX-FS Ethernet MAC.\n");
+        error_report("Unconnected ETRAX-FS Ethernet MAC");
+        return -1;
     }
 
     s->dma_out->client.push = eth_tx_push;