gpu: update README to better reflect current limitations

Update the README to better reflect the limitations of not supporting blob
resources and remove the note about hardcoded number of capsets that has been
fixed.

Signed-off-by: Matej Hrica <[email protected]>

Author: mtjhrc

staging/vhost-device-gpu/README.md

@@ -75,14 +75,11 @@ resources. It'll be nice to have support for directly sharing display output
 resource using dmabuf.
 
 This device does not yet support the `VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB`,
-`VIRTIO_GPU_CMD_SET_SCANOUT_BLOB` and `VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID` features.
-
-Currently this crate requires some necessary bits in order to move the crate out of staging:
-
-- Addition of CLI arguments to specify the exact number of capsets and use
-  a default capset configuration when no capset is specified rather than using
-  hard-coded capset value.
-
+`VIRTIO_GPU_CMD_SET_SCANOUT_BLOB` and `VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID` features. 
+This requires https://github.com/rust-vmm/vhost/pull/251, which in turn requires QEMU API stabilization.
+Because blob resources are not yet supported, some capsets are limited:
+- Venus (Vulkan implementation in virglrenderer project) support is not available at all.
+- gfxstream-vulkan and gfxstream-gles support are exposed, but can practically only be used for display output, there is no hardware acceleration yet.
 ## Features
 
 The device leverages the [rutabaga_gfx](https://crates.io/crates/rutabaga_gfx)