x11-drivers/xf86-video-mga: Update to 2.1.0

Update WWW and pkg-descr.
Add LICENSE.

https://lists.x.org/archives/xorg-announce/2022-July/003184.html
https://lists.x.org/archives/xorg-announce/2024-October/003539.html

PR: 296281
Approved by: x11 (arrowd)
Approved by: fluffy (mentor)