i915_gem.c: Revisit initialization code
drm2: Comment out i915_info_sysctl_handler()
drm: disable drm_kms_helper_poll for now
drm2: Hook to DragonFly's build infrastructure

* The drm2+i915 code is built as kernel modules only

* Remove unneeded dependency on 'mem' device
drm/i915: Add no-lvds quirk for Supermicro X7SPA-H

Reported-and-tested-by: Francois Tigeot <ftigeot@wolfpond.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=55375
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm: Properly initialize drm_debug_flag

- If DRM_DEBUG_DEFAULT_ON is defined, then initialize drm_debug_flagi to
  all supported debugging bits.
- If DRM_DEBUG_DEFAULT_ON isn't defined, then initialize drm_debug_flag
  to zero.

DRM_DEBUG_DEFAULT_ON is defined when module is build with -DDEBUG_DRM
or if kernel config has 'options DEBUG_DRM'.

Reviewed by:	kib
msgport.9: lwkt_dropmsg returns an int.
dlvsym.3: Restrict to documenting dlvsym().

* Remove wrong prototype. dlsym() has its own manual page which has it
  correctly.

* Do not reference itself in SEE ALSO.

* Fix .Nm
getfsstat.2: Fix getvfsstat() prototype.
getmntopts.3: Adjust manpage prototype.
atomic.9: add brackets in a C snippet