mptsas: add missing va_end

Reported by Coverity.

Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/scsi/mptconfig.c

@@ -123,6 +123,7 @@ static size_t vpack(uint8_t **p_data, const char *fmt, va_list ap1)
         va_copy(ap2, ap1);
         size = vfill(NULL, 0, fmt, ap2);
         *p_data = data = g_malloc(size);
+        va_end(ap2);
     }
     return vfill(data, size, fmt, ap1);
 }