5255 uts shouldn't open-code ISP2

*** 30,39 ****
--- 30,40 ----
   *
   *    Implements the routines necessary for initializing and (later) tearing
   *    down the list of Tavor configuration information.
   */
  
+ #include <sys/sysmacros.h>
  #include <sys/types.h>
  #include <sys/conf.h>
  #include <sys/ddi.h>
  #include <sys/sunddi.h>
  #include <sys/modctl.h>
*** 655,665 ****
           * with all the other headers and alignment restrictions, sets the
           * maximum for the number of SGLs that we can advertise support for.
           */
          max_size = (TAVOR_QP_WQE_MLX_QP1_HDRS + (max_sgl << 4));
          log2 = highbit(max_size);
!         if ((max_size & (max_size - 1)) == 0) {
                  log2 = log2 - 1;
          }
          max_size = (1 << log2);
  
          /*
--- 656,666 ----
           * with all the other headers and alignment restrictions, sets the
           * maximum for the number of SGLs that we can advertise support for.
           */
          max_size = (TAVOR_QP_WQE_MLX_QP1_HDRS + (max_sgl << 4));
          log2 = highbit(max_size);
!         if (ISP2(max_size)) {
                  log2 = log2 - 1;
          }
          max_size = (1 << log2);
  
          /*