libdrm: (revised) vblank wait on crtc > 1

Hi Alex,

Enclosed is a revised version of the patch sent on Mar 18, against
the master branch of the drm userspace (i.e. libdrm). Details
summarised in this thread:
http://lists.freedesktop.org/archives/dri-devel/2011-March/009499.html



This patch reconciles libdrm with the the kernel change that Dave
pushed this morning. It *supersedes* the previously sent patch (i.e.
apply it to the master branch as it exists at the time of this writing,
not as an incremental patch to the one sent previously).

Regards,

Ilija

Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>