Attn: Quiesce host on SBE vital

When an SBE vital is detected the attention handler will transition the
host to the quiesce state. Code has also been added to make a call to
thread_stop_all (libpdbg) before transitioning host (mpipl and
quiesce cases).

Signed-off-by: Ben Tyner <ben.tyner@ibm.com>
Change-Id: Idac4680e2cb9eacedb6be7b70ae8b0d60dde66b5
diff --git a/attn/vital_handler.hpp b/attn/vital_handler.hpp
new file mode 100644
index 0000000..e1ae4ac
--- /dev/null
+++ b/attn/vital_handler.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+namespace attn
+{
+
+/**
+ * @brief Handle SBE vital attention
+ *
+ * @param i_attention Attention object
+ * @return 0 indicates that the vital attention was successfully handled
+ *         1 indicates that the vital attention was NOT successfully handled
+ */
+int handleVital(Attention* i_attention);
+
+} // namespace attn