Integrated video does not have its own RAM (most people consider this to be the distinguishing factor between an integrated vs discrete GPU - the latter has its own dedicated RAM called video RAM or VRAM).
Instead, integrated video will use system RAM as VRAM. This RAM is slower (a lot slower) than true VRAM, but outside of hardcore gaming it's usually fast enough. Since a GPU will always need some RAM, an integrated GPU will always reserve some system RAM for its exclusive use. In your case, this is 128 MB. However, if it needs more, it can use more system RAM (at the cost of preventing programs from using that RAM). In your case it can use up to 2176 MB of system RAM when needed.
For most purposes, leaving it at 128 MB reserved should be fine. The only time you really need to increase it is if you're low on system RAM. e.g. You've got 4 GB of RAM, and when gaming you're using 3.8 GB. But you want the video to be able to use up to 512 MB of RAM as VRAM (forcing the game to swap to disk but giving you prettier graphics). In that case you'll want to bump up the RAM reserved for video up to 512 MB.