hw/mips/mips_malta: don't make bios region 'nomigrate'

Currently we use memory_region_init_rom_nomigrate() to create
the "bios.1fc" memory region, and we don't manually register
it with vmstate_register_ram(). This currently means that its
contents are migrated but as a ram block whose name is the empty
string; in future it may mean they are not migrated at all. Use
memory_region_init_ram() instead.

Note that this is a a cross-version migration compatibility break
for the "malta" machine.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>

hw/mips/mips_malta.c

@@ -1152,7 +1152,7 @@ void mips_malta_init(MachineState *machine)
      * handled by an overlapping region as the resulting ROM code subpage
      * regions are not executable.
      */
-    memory_region_init_ram_nomigrate(bios_copy, NULL, "bios.1fc", BIOS_SIZE,
+    memory_region_init_ram(bios_copy, NULL, "bios.1fc", BIOS_SIZE,
                            &error_fatal);
     if (!rom_copy(memory_region_get_ram_ptr(bios_copy),
                   FLASH_ADDRESS, BIOS_SIZE)) {