10096 kstat update routines shouldn't check for NULL kstat

*** 21,30 ****
--- 21,34 ----
  
  /*
   * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
   */
  
+ /*
+  * Copyright (c) 2018, Joyent, Inc.
+  */
+ 
  #include <sys/types.h>
  #include <sys/stream.h>
  #include <sys/cmn_err.h>
  #define _SUN_TPI_VERSION 2
  #include <sys/tihdr.h>
*** 58,68 ****
          netstackid_t    stackid = (netstackid_t)(uintptr_t)kp->ks_private;
          netstack_t      *ns;
          sctp_stack_t    *sctps;
          mib2_sctp_t     sctp_mib;
  
!         if (kp == NULL|| kp->ks_data == NULL)
                  return (EIO);
  
          if (rw == KSTAT_WRITE)
                  return (EACCES);
  
--- 62,72 ----
          netstackid_t    stackid = (netstackid_t)(uintptr_t)kp->ks_private;
          netstack_t      *ns;
          sctp_stack_t    *sctps;
          mib2_sctp_t     sctp_mib;
  
!         if (kp->ks_data == NULL)
                  return (EIO);
  
          if (rw == KSTAT_WRITE)
                  return (EACCES);