Print a line in dmesg to indicate if the aperture driver is
required to run X. This will be used by the installer to decide
what value to set machdep.allowaperture to.

For devices supported by i915 and radeon kms machdep.allowaperture
will be set to 0. Systems that have a graphics device commonly
found in servers (g200e*/aspeed/es1000 etc) will also not have
the aperture enabled as they generally don't need to run X.

ok deraadt@ kettenis@