As speculation grows over the possibility Apple is working on a foldable iPhone or tablet, UBS took a look at the boost the company could get from such a device. "While our preliminary checks do not incorporate a foldable smartphone into our model, we think that such a device could be an incremental opportunity for future generation iPhone models," UBS analyst David Vogt wrote in a note to clients Tuesday. The technology giant received a patent Tuesday for electronic devices with display and touch sensor structures, with the patent abstract specifically noting a "foldable electronic device" that might have a…