Radeon 780M support

[Thomas Klausner <wiz%netbsd.org@localhost>]

Hi!

I found this on Mastodon:

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This is my changeset in order to use amdgpu module with my card -
Radeon 780M, coming with an AMD Ryzen 7 8845HS. It's applied on top of
NetBSD 11.0. It's a minimal changeset, much of the stuff is disabled -
e.g. AGP etc.

My card PCI ID is 0x1002 0x1900, but I suspect that this changeset
works with other newer Radeons. If you want to give it a try you have
to add your pci id in
sys/external/bsd/drm2/dist/drm/amd/amdgpu/amdgpu_drv.c. Unlike Linux,
wildcard probing is disabled.
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https://github.com/mchelaru/netbsd-drm-src/tree/netbsd-11

see the README.md for more details.

Here are the actual commits:

https://github.com/NetBSD/src/compare/netbsd-11...mchelaru:netbsd-drm-src:netbsd-11

Perhaps someone can merge this...
 Thomas