cleanup: Drop pointless return at end of function

A few functions now end with a label.  The next commit will clean them
up.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250407082643.2310002-3-armbru@redhat.com>
[Straightforward conflict with commit 988ad4cceb (hw/loongarch/virt:
Fix cpuslot::cpu set at last in virt_cpu_plug()) resolved]

linux-user/xtensa/signal.c

@@ -241,7 +241,6 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
 give_sigsegv:
     force_sigsegv(sig);
-    return;
 }
 
 static void restore_sigcontext(CPUXtensaState *env,