The only place to increase your Integrated Graphics vRAM is through BIOS Settings.
Look in BIOS for any settings concerning the IGPU. If there isn't a settings in BIOS to increase or decrease the IGPU vRAM then DELL made it permanent the amount you have.
Besides, Windows will automatically allocate whatever System RAM your IGPU needs to run a game or program. Increasing vRAM on the IGPU might make it run more efficiently and probably a little bit better. But I would look to see if your laptop hardware is able to run your games at high, medium or low settings by going to one of these Can I Run It websites:
System Requirements Lab.com - Can I Run It
PC Game Benchmark.com - Can I Run It
PC Builds - Can I Run It
NOTE: Also depends on how much System RAM you have installed in the laptop if it is advisable to increase your IGPU vRAM.
