fw_cfg_mem: flip ctl_mem_ops and data_mem_ops to DEVICE_BIG_ENDIAN

The standalone selector port (fw_cfg_ctl_mem_ops) is only used by big
endian guests to date (*), hence this change doesn't regress them. Paolo
and Alex have suggested / requested an explicit DEVICE_BIG_ENDIAN setting
here, for clarity.

(*) git grep -l fw_cfg_init_mem

    hw/nvram/fw_cfg.c
    hw/ppc/mac_newworld.c
    hw/ppc/mac_oldworld.c
    hw/sparc/sun4m.c
    include/hw/nvram/fw_cfg.h

The standalone data port (fw_cfg_data_mem_ops) has max_access_size 1 (for
now), hence changing its endianness doesn't change behavior for existing
guest code.

Signed-off-by: Laszlo Ersek <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Message-id: [email protected]
Signed-off-by: Peter Maydell <[email protected]>

hw/nvram/fw_cfg.c

@@ -332,14 +332,14 @@ static bool fw_cfg_comb_valid(void *opaque, hwaddr addr,
 
 static const MemoryRegionOps fw_cfg_ctl_mem_ops = {
     .write = fw_cfg_ctl_mem_write,
-    .endianness = DEVICE_NATIVE_ENDIAN,
+    .endianness = DEVICE_BIG_ENDIAN,
     .valid.accepts = fw_cfg_ctl_mem_valid,
 };
 
 static const MemoryRegionOps fw_cfg_data_mem_ops = {
     .read = fw_cfg_data_mem_read,
     .write = fw_cfg_data_mem_write,
-    .endianness = DEVICE_NATIVE_ENDIAN,
+    .endianness = DEVICE_BIG_ENDIAN,
     .valid = {
         .min_access_size = 1,
         .max_access_size = 1,