10099 libfakekernel vpanic() should cast away assfail()

*** 21,30 ****
--- 21,31 ----
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2012 by Delphix. All rights reserved.
   * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
   * Copyright 2017 RackTop Systems.
+  * Copyright (c) 2018, Joyent, Inc.
   */
  
  #include <sys/param.h>
  #include <sys/types.h>
  #include <sys/varargs.h>
*** 113,123 ****
          va_copy(tmpargs, adx);
          fakekernel_cprintf(fmt, tmpargs, SL_FATAL, "fatal: ", "\n");
  
          /* Call libc`assfail() so that mdb ::status works */
          (void) vsnprintf(panicbuf, sizeof (panicbuf), fmt, adx);
!         assfail(panicbuf, "(panic)", 0);
  
          abort();        /* avoid "noreturn" warnings */
  }
  
  void
--- 114,124 ----
          va_copy(tmpargs, adx);
          fakekernel_cprintf(fmt, tmpargs, SL_FATAL, "fatal: ", "\n");
  
          /* Call libc`assfail() so that mdb ::status works */
          (void) vsnprintf(panicbuf, sizeof (panicbuf), fmt, adx);
!         (void) assfail(panicbuf, "(panic)", 0);
  
          abort();        /* avoid "noreturn" warnings */
  }
  
  void