I'm not 100% sure but i think the maximum gadgets you can carry is three?, well looking at the upgrades it says "capacity" 1-3. I think you have a default Portable EMP and whatever other two gadgets you choose in your optional loadout screen. I'll have to double check though because i normaly play with pistols only and gadgets off.
Well kinda they did i guess. The suit gadget upgrades don't allow you to have another *type* of gadget in addition to the portable EMP and whatever 2 gadgets you already got on you, the suit upgrade simply gives you one extra gadget for each of your currently equipped gadgets. Meaning that you will have one more EMP/Mine/Flashbang to shove into someones face for each upgrade you equip on your suit... ^^ Mind that these upgrades DON'T give you extra portable EMPs ^^