mac_nvram: Mark as Big Endian

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/hw/mac_nvram.c b/hw/mac_nvram.c
index bcde07d..0a22e66 100644
--- a/hw/mac_nvram.c
+++ b/hw/mac_nvram.c
@@ -96,7 +96,7 @@
 static const MemoryRegionOps macio_nvram_ops = {
     .read = macio_nvram_readb,
     .write = macio_nvram_writeb,
-    .endianness = DEVICE_NATIVE_ENDIAN,
+    .endianness = DEVICE_BIG_ENDIAN,
 };
 
 static const VMStateDescription vmstate_macio_nvram = {