5045 use atomic_{inc,dec}_* instead of atomic_add_*

*** 92,102 ****
                  if (end > mem_node_config[mnode].physmax)
                          mem_node_config[mnode].physmax = end;
          } else {
                  mem_node_config[mnode].physbase = start;
                  mem_node_config[mnode].physmax = end;
!                 atomic_add_16(&num_memnodes, 1);
                  do {
                          oldmask = memnodes_mask;
                          newmask = memnodes_mask | (1ull << mnode);
                  } while (atomic_cas_64(&memnodes_mask, oldmask, newmask) !=
                           oldmask);
--- 92,102 ----
                  if (end > mem_node_config[mnode].physmax)
                          mem_node_config[mnode].physmax = end;
          } else {
                  mem_node_config[mnode].physbase = start;
                  mem_node_config[mnode].physmax = end;
!                 atomic_inc_16(&num_memnodes);
                  do {
                          oldmask = memnodes_mask;
                          newmask = memnodes_mask | (1ull << mnode);
                  } while (atomic_cas_64(&memnodes_mask, oldmask, newmask) !=
                           oldmask);
*** 158,168 ****
                  ASSERT(MNODE_PGCNT(mnode) == 0);
                  do {
                          omask = memnodes_mask;
                          nmask = omask & ~(1ull << mnode);
                  } while (atomic_cas_64(&memnodes_mask, omask, nmask) != omask);
!                 atomic_add_16(&num_memnodes, -1);
                  mem_node_config[mnode].exists = 0;
          }
  }
  
  void
--- 158,168 ----
                  ASSERT(MNODE_PGCNT(mnode) == 0);
                  do {
                          omask = memnodes_mask;
                          nmask = omask & ~(1ull << mnode);
                  } while (atomic_cas_64(&memnodes_mask, omask, nmask) != omask);
!                 atomic_dec_16(&num_memnodes);
                  mem_node_config[mnode].exists = 0;
          }
  }
  
  void
*** 228,238 ****
          if (mnode >= max_mem_nodes)
                          panic("Out of free memnodes\n");
  
          mem_node_config[mnode].physbase = (uint64_t)-1;
          mem_node_config[mnode].physmax = 0;
!         atomic_add_16(&num_memnodes, 1);
          do {
                  oldmask = memnodes_mask;
                  newmask = memnodes_mask | (1ull << mnode);
          } while (atomic_cas_64(&memnodes_mask, oldmask, newmask) != oldmask);
  
--- 228,238 ----
          if (mnode >= max_mem_nodes)
                          panic("Out of free memnodes\n");
  
          mem_node_config[mnode].physbase = (uint64_t)-1;
          mem_node_config[mnode].physmax = 0;
!         atomic_inc_16(&num_memnodes);
          do {
                  oldmask = memnodes_mask;
                  newmask = memnodes_mask | (1ull << mnode);
          } while (atomic_cas_64(&memnodes_mask, oldmask, newmask) != oldmask);