Import VGA files from xen-unstable tip 17647:f12724194ec6

Import VGA files from xen-unstable tip 17647:f12724194ec6

The following files
   console.c
   hw/cirrus_vga.c
   hw/cirrus_vga_rop.h
   hw/cirrus_vga_rop2.h
   hw/vga.c
   hw/vga_int.h
   hw/vga_template.h
are hereby transplated verbatim from xen-unstable.  This represents
all of the changes on xen-unstable since qemu 0.9.0, which is the last
merged version.  We will now cherry-pick commits from the master qemu
branch, and then merge-choosing-ours, which will result in a history
which claims to be a merge between qemu and xen but which has only the
cherrypicked changes from qemu.