vt: Add vd_bitblt_argb

[manu]

Summary

This blit an ARGB image on the dedicated vd.
This also adds vt_fb_bitblt_argb which will works for most of the vt backends

Sponsored by: Beckhoff Automation GmbH & Co. KG

[andrew]

Should we add vd_bitblt_argb implementations to simplefb and virtio-gpu?

[manu]

In D45929#1047114, @andrew wrote:

Should we add vd_bitblt_argb implementations to simplefb and virtio-gpu?

For simplefb the current form will only work with the a8r8g8b8 and x8r8g8b8 form so we need some kind of validation first.
I was planning to do that after (I need to dig up some arm64 boards and update them before working on this).
Where is the virtio-gpu stuff ?

[manu]

In D45929#1047205, @manu wrote:

In D45929#1047114, @andrew wrote:

Should we add vd_bitblt_argb implementations to simplefb and virtio-gpu?

For simplefb the current form will only work with the a8r8g8b8 and x8r8g8b8 form so we need some kind of validation first.
I was planning to do that after (I need to dig up some arm64 boards and update them before working on this).
Where is the virtio-gpu stuff ?

But I should probably do a stub which returns EOPNOTSUPP for now otherwise we will panic

[manu]

Add stub for simplefb

[andrew]

In D45929#1047205, @manu wrote:

Where is the virtio-gpu stuff ?

sys/dev/virtio/gpu

[manu]

Add a stub for virtio_gpu