Hey! 

If placements are the only concerned factor for choosing the college for you , then you must go for Thapar university. Thapar university has good name in the market of universities , so many reputed companies like amazon , micrisoft , google come to this university for recruitments whereas , these companies don't go to LMNIIT.  Also , the placement packages of Thapar university are far better than LMNIIT. 

Hope it helps!