softmmu: List CPU types again

Commit e0220bb5b2 made cpus.c target-agnostic but didn't notice
the cpu_list() function is only defined in target-specific code
in "cpu.h". Move list_cpus() declaration to "exec/cpu-common.h"
because this function is not softmmu-specific and can also be
used by user-mode, along with moving its implementation to cpu.c,
which is compiled per target.

Fixes: e0220bb5b2 ("softmmu: Build target-agnostic objects once")
Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220314140108.26222-1-philippe.mathieu.daude@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

cpu.c

@@ -35,6 +35,7 @@
 #include "sysemu/tcg.h"
 #include "sysemu/kvm.h"
 #include "sysemu/replay.h"
+#include "exec/cpu-common.h"
 #include "exec/exec-all.h"
 #include "exec/translate-all.h"
 #include "exec/log.h"
@@ -266,6 +267,14 @@ const char *parse_cpu_option(const char *cpu_option)
     return cpu_type;
 }
 
+void list_cpus(const char *optarg)
+{
+    /* XXX: implement xxx_cpu_list for targets that still miss it */
+#if defined(cpu_list)
+    cpu_list();
+#endif
+}
+
 #if defined(CONFIG_USER_ONLY)
 void tb_invalidate_phys_addr(target_ulong addr)
 {

include/exec/cpu-common.h

@@ -158,4 +158,6 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
 /* vl.c */
 extern int singlestep;
 
+void list_cpus(const char *optarg);
+
 #endif /* CPU_COMMON_H */

include/sysemu/cpus.h

@@ -55,6 +55,4 @@ extern int smp_cores;
 extern int smp_threads;
 #endif
 
-void list_cpus(const char *optarg);
-
 #endif

softmmu/cpus.c

@@ -728,14 +728,6 @@ int vm_stop_force_state(RunState state)
     }
 }
 
-void list_cpus(const char *optarg)
-{
-    /* XXX: implement xxx_cpu_list for targets that still miss it */
-#if defined(cpu_list)
-    cpu_list();
-#endif
-}
-
 void qmp_memsave(int64_t addr, int64_t size, const char *filename,
                  bool has_cpu, int64_t cpu_index, Error **errp)
 {