Follow r261352 by updating all drivers which are children of simplebus
  to check the status property in their probe routines.

    r257368, r257416

  Hints-only devices should return BUS_PROBE_NOWILDCARD from their probe
  methods.

  Make different bus attachments for Altera and Terasice
  device drivers share the same devclass_t.

Sponsored by:	DARPA, AFRL

  Consistently use the vendor name "sri-cambridge" for device
  compatibility strings on the BERI platform.

Sponsored by:	DARPA, AFRL

  Write FDT attachment for the Terasic MTL (multitouch LCD) driver.
  Exploit the fact that FDT allows multiple memory ranges to be
  assigned to a device, giving us a cleaner description than
  device.hints does.

Portions of this changeset that remove mtl from BERI device.hints and
add to DTS will be merged separately.

Sponsored by:	DARPA, AFRL

  Copy Terasic MTL nexus bus attachment as a starting point for an
  FDT attachment for the same driver.

Sponsored by:	DARPA, AFRL

  Update nexus parts in copied DE4LED attachment to use FDT.

Sponsored by:	DARPA, AFRL

  Copy DE4 LED nexus bus attachment as a starting point for an FDT
  attachment.

Sponsored by:	DARPA, AFRL

Terasic DE-4 board.  Allow LED configuration to be set using loader
tunables, not just from userspace, and preconfigure LED 8 as a kernel
heartbeat.  For now, this is a Nexus-attached, BERI-only driver, but it
could be used with other hard and soft cores on Altera FPGAs as well, in
principle.

Sponsored by:	DARPA, AFRL

used with Terasic's DE-4 and other similar FPGA boards.  This display
is 800x480 and includes a capacitive touch screen, multi-touch
gesture recognition, etc.  This device driver depends on a Cambridge-
provided IP core that allows the MTL device to be hooked up to the
Altera Avalon SoC bus, and also provides a VGA-like text frame buffer.

Although it is compiled as a single device driver, it actually
implements a number of different device nodes exporting various
aspects of this multi-function device to userspace:

- Simple memory-mapped driver for the MTL 24-bit pixel frame buffer.
- Simple memory-mapped driver for the MTL control register set.
- Simple memory-mapped driver for the MTL text frame buffer.
- syscons attachment for the MTL text frame buffer.

This driver attaches directly to Nexus as is common for SoC device
drivers, and for the time being is considered BERI-specific, although
in principle it might be used with other hard and soft cores on
Altera FPGAs.

Control registers, including touchscreen input, are simply memory
mapped; in the future it would be desirable to hook up a more
conventional device node that can stream events, support kqueue(2)/
poll(2)/select(2), etc.

This is the first use of syscons on MIPS, as far as I can tell, and
there are some loose ends, such as an inability to use the hardware
cursor.  More fundamentally, it appears that syscons(4) assumes that
either a host is PC-like (i386, amd64) *or* it must be using a
graphical frame buffer.  While the MTL supports a graphical frame
buffer, using the text frame buffer is preferable for console use.
Fixing this issue in syscons(4) requires non-trivial changes, as the
text frame buffer support assumes that direct memory access can be
done to the text frame buffer without using bus accessor methods,
which is not the case on MIPS.  As a workaround for this, we instead
double-buffer and pretend to be a graphical frame buffer exposing
text accessor methods, leading to some quirks in syscons behaviour.

Sponsored by:	DARPA, AFRL