Bump MEMSTAT_MAXCALLER to 16.  memtop(8) seems to be able to happily consume that many slots to track snapshot-to-snapshot changes and running totals.  And 16 is a nice round number.
Bump MEMSTAT_MAXCALLER to 16.  memtop(8) seems to be able to happily
consume that many slots to track snapshot-to-snapshot changes and
running totals.  And 16 is a nice round number.

MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase