radeon driver updates for mac laptops

["Alex Deucher" <alexdeucher@gmail.com>]

Those of you with radeon based mac laptops please test the latest code
in that ati git tree.  I recently added connector table and quirk
information for mac laptops.  You will need at least xserver 1.3 and a
recent version of xrandr (1.2.2 preferred) to test.

As far as I can tell there are three apple laptop variants:

ibook                              - LVDS, TVDAC drives TV or VGA via dongle
powerbook-duallink   - LVDS, TV, External TMDS/Primary DAC
powerbook                   - LVDS, TV, Internal TMDS/Primary DAC

To test, add:

Option "MacModel" "<string>"

to the device section of your xorg config where <string> is one of the
following:
ibook
powerbook-duallink
powerbook

powerbook-duallink indicates that it is one of the laptops that has
dual link DVI rather than single link.  We can't yet init the external
dual link TMDS directly, but if OF inits it, it should work.  I'm also
not sure about some of the pll quirks for ibooks. those may not be
needed in all cases.

Please test and let me know how it goes, as I don't have any macs and
we may need additional quirks or finer grained model info.  Also, make
sure I'm cc'ed as I'm not on this list.

Thanks!

Alex