Panic radeonkms ttm between r265233M and r268249

[J.R. Oldroyd]

Using 10-stable svn'd on 2014/05/01 r265233M with VT kernel and radeonkms
enabled, ACPI suspend/resume work fine.  I can suspend and resume the
laptop endlessly (and did so for about two months without any crash or
reboot).

Update to 10-stable of 2014/07/04 r268249 and now the resume causes an
immediate panic.

Good logs here:

http://opal.com/jr/radeonkms/20140501-radeon_r300_boot_ok.txt
http://opal.com/jr/radeonkms/20140501-radeon_resume_ok.txt

Logs showing the panic here:

http://opal.com/jr/radeonkms/20140704-radeon_r300_boot_fail.txt
http://opal.com/jr/radeonkms/20140704-radeon_resume_panic.txt

In fact, the 07/04 kernel fails to init the radeon ring CP properly
which causes X.org to not load libdri2.so and r300_dri.so as I posted
about separately.

Kernel and all X.org ports updated and compiled locally for both
versions.

	-jr