Not sure I would want to do this, however .. you could write a SP that uses a cursor with the basic select tabschema, tabname query, fetch those values into schema and name defined variables, looping through each fetch using something like SET REO_TXT = 'call admin_cmd(''reorg table '||v_schema||'.'||v_tabname||')'; and EXECUTE IMMEDIATE reo_txt; before moving on to the next in the loop.
Not tested but you should get the idea, again not sure I would want to do this but the logic should work.
Frankly, reorging all the tables all at once is overkill. Many may not need a reorg at all. In my opinion, there should be a particular need to perform a reorg. You realize that because this process reorgs every table, the the system is essentially offline while this is happening.
I agree with ARWinner. Nevertheless if the database is very small and if you are sure that no activity is running on it, you can try. You can also run an online reorg, which allows you to run the application in parallel, but the performance will suffer.
Don't forget, after the reorg is done, to run the runstats and if you have statics sql you need to rebind the packages using the reorganized tables.