Patch for qemu-project/qemu#2247 issue

[liu.dayu]

hmp: Add help information for watchdog action: inject-nmi

virsh qemu-monitor-command --hmp help information of watchdog_action missing 
inject-nmi which already supported in Commit 795dc6e4

Signed-off-by: Dayu Liu <liu.dayu@zte.com.cn>

---
 hmp-commands.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 772ab996a..bc7e6d1dc 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1412,7 +1412,7 @@ ETEXI
     {
         .name       = "watchdog_action",
         .args_type  = "action:s",
-        .params     = "[reset|shutdown|poweroff|pause|debug|none]",
+        .params     = "[reset|shutdown|poweroff|pause|debug|none|inject-nmi]",
         .help       = "change watchdog action",
         .cmd        = hmp_watchdog_action,
         .command_completion = watchdog_action_completion,
--