revert pci modern virtio transport

The FROMLIST patch simply has too many bugs to be worth using. Because
there are no plans to make use of virtio-gpu, we don't even need it.

Revert "fix some bit shift bugs in pci modern ops"
Revert "FROMLIST: kvmtool: add support for modern virtio-pci"

TEST=emerge-samus kvmtool
BUG=None

Change-Id: I59b0e9737dc449c2940d93a3e254e333df660734
Reviewed-on: https://chromium-review.googlesource.com/465419
Commit-Ready: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: Chirantan Ekbote <chirantan@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
22 files changed