Framebuffer console support for i386 and amd64

["Jared D. McNeill" <jmcneill%invisible.ca@localhost>]

Hey folks --

My goal is to nuke vesafb, and replace it with genfb in the i386 and 
amd64 kernels. This is a prereq to having proper splash screen support. 
I would like to check in the following changes to the x86 bootloader and 
kernel. Any objections?

  http://www.invisible.ca/~jmcneill/outgoing/x86fb/

With the above changes and the proper options in your kernel config, you 
can select a framebuffer mode in the bootloader by doing 'vesa modenum', 
so a boot.cfg entry would look like this for eg. 640x480x8:

  menu=Boot NetBSD:vesa 0x101;boot netbsd

The required kernel options are:

  genfb*  at pci? dev ? function ?
  wsdisplay* at wsemuldisplaydev?

Cheers,
Jared