Update patch for 8.2+

See https://gitlab.com/qemu-project/qemu/-/commit/8d7f2e767d8cd058c817dbe31430b89f2e11535d ("softmmu/" -> "system/")

8.2-rc/qemu-signals.patch

@@ -1,10 +1,10 @@
 Origin: https://bugs.launchpad.net/qemu/+bug/1217339/comments/2
 Origin: https://lists.nongnu.org/archive/html/qemu-devel/2017-03/msg03039.html
 
-diff --git a/softmmu/runstate.c b/softmmu/runstate.c
+diff --git a/system/runstate.c b/system/runstate.c
 index ce8977c6a2..392e4c88be 100644
---- a/softmmu/runstate.c
-+++ b/softmmu/runstate.c
+--- a/system/runstate.c
++++ b/system/runstate.c
 @@ -613,7 +613,11 @@ void qemu_system_killed(int signal, pid_t pid)
      /* Cannot call qemu_system_shutdown_request directly because
       * we are in a signal handler.