monitor: Do not check TARGET_I386/RISCV to build 'info mem' command

This command is filtered at build-time for i386/x86_64 and
riscv32/riscv64 binaries. By using the recently introduced
HMPCommand::arch_bitmask flag we can filter it at runtime,
making it possible to compile hmp-commands-info.hx once.

Since the method depends on a pair of distinct targets,
define it in its own stub file.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20260427080738.77138-18-philmd@linaro.org>

stubs/hmp-cmd-info_mem.c

@@ -0,0 +1,12 @@
+/*
+ * Human Monitor 'info mem' stub
+ *
+ * Copyright (c) Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "monitor/hmp.h"
+
+HMP_STUB(info_mem)

stubs/meson.build

@@ -87,6 +87,7 @@ if have_system
   stub_ss.add(files('qmp-cpu.c'))
   stub_ss.add(files('qmp-cpu-s390x.c'))
   stub_ss.add(files('qmp-cpu-s390x-kvm.c'))
+  stub_ss.add(files('hmp-cmd-info_mem.c'))
   stub_ss.add(files('hmp-cmd-info_sev.c'))
   stub_ss.add(files('hmp-cmds-hw-s390x.c'))
   stub_ss.add(files('hmp-cmds-target-i386.c'))