sysbus: Supply missing va_end()

C99 7.15.1: Each invocation of the va_start and va_copy macros shall
be matched by a corresponding invocation of the va_end macro in the
same function.

Spotted by Coverity.  Harmless on the (common) systems where va_end()
does nothing.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

hw/sysbus.c

@@ -198,6 +198,7 @@ DeviceState *sysbus_create_varargs(const char *name,
         sysbus_connect_irq(s, n, irq);
         n++;
     }
+    va_end(va);
     return dev;
 }
 
@@ -229,6 +230,7 @@ DeviceState *sysbus_try_create_varargs(const char *name,
         sysbus_connect_irq(s, n, irq);
         n++;
     }
+    va_end(va);
     return dev;
 }