Two businesses in Lansdale can start reaping the benefits of the borough economic incentive program.   Berk Wiper Converting and Packaging on North Valley Forge Road and Tyco Fire Protection Products on Pennbrook Parkway got the approval from borough council Wednesday night.   Berk will get a 5% discount on its electric rate for the next two years.   It earned that by investing more than $500,000 in its existing facility and employing 15 workers there.   Tyco is getting a 5% electric rate discount for five years after spending more than $1,000,000 on its plant and maintaining an employee level of 30 workers.  Both businesses have the option of taking their incentive retroactively or using it going forward.   The idea behind the program is to bring new businesses into Lansdale and help the borough retain the ones that are already there.