hppa: drop usage of memory_region_allocate_system_memory() for ROM

machine_hppa_init() violates memory_region_allocate_system_memory() contract
by calling it multiple times which could break with -mem-path. Replace
the second usage (for 'rom') with memory_region_init_ram() instead.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20191008113318.7012-4-imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

hw/hppa/machine.c

@@ -161,9 +161,8 @@ static void machine_hppa_init(MachineState *machine)
     g_free(firmware_filename);
 
     rom_region = g_new(MemoryRegion, 1);
-    memory_region_allocate_system_memory(rom_region, OBJECT(machine),
-                                         "firmware",
-                                         (FIRMWARE_END - FIRMWARE_START));
+    memory_region_init_ram(rom_region, NULL, "firmware",
+                           (FIRMWARE_END - FIRMWARE_START), &error_fatal);
     memory_region_add_subregion(addr_space, FIRMWARE_START, rom_region);
 
     /* Load kernel */