target/arm: Move the reference to arm-core.xml

Some subclasses overwrite gdb_core_xml_file member but others don't.
Always initialize the member in the subclasses for consistency.

This especially helps for AArch64; in a following change, the file
specified by gdb_core_xml_file is always looked up even if it's going to
be overwritten later. Looking up arm-core.xml results in an error as
it will not be embedded in the AArch64 build.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230912224107.29669-7-akihiko.odaki@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231009164104.369749-14-alex.bennee@linaro.org>

target/arm/cpu.c

@@ -2392,7 +2392,6 @@ static void arm_cpu_class_init(ObjectClass *oc, void *data)
     cc->sysemu_ops = &arm_sysemu_ops;
 #endif
     cc->gdb_num_core_regs = 26;
-    cc->gdb_core_xml_file = "arm-core.xml";
     cc->gdb_arch_name = arm_gdb_arch_name;
     cc->gdb_get_dynamic_xml = arm_gdb_get_dynamic_xml;
     cc->gdb_stop_before_watchpoint = true;
@@ -2414,8 +2413,10 @@ static void arm_cpu_instance_init(Object *obj)
 static void cpu_register_class_init(ObjectClass *oc, void *data)
 {
     ARMCPUClass *acc = ARM_CPU_CLASS(oc);
+    CPUClass *cc = CPU_CLASS(acc);
 
     acc->info = data;
+    cc->gdb_core_xml_file = "arm-core.xml";
 }
 
 void arm_cpu_register(const ARMCPUInfo *info)