Make .INVISIBLE nodes be ignored by suffix transformations.
use .INVISIBLE to hide random.S, instead of extra rules.
Fix i915 locking around error handling.
The 4 second timeout of the invafd test case is not always enough when
running under qemu; increase it to 10 seconds.
Split some long lines.
Fix two mistakes in previous.

- i915_error_wake_up is given irq_lock, so it need not take that.
- Unlock irq_lock on exit from i915_hangcheck_elapsed if ring_hung.

XXX This introduces the lock order irq_lock -> pending_flip_lock.
How about just using irq_lock for pending flips?
Convert linux_kmap_lock to an adaptive lock.

kmap/kunmap can't be used in interrupt context anyway, so there is no
need for this to be a spin lock.
Simplify empty test for linux_kmap_entries.
Assert sleepable in Linux kmap/kunmap.
__diagused, not __unused.
Tweak style.

No functional change intended.  Assembly differences appear to be
only related to kassert line numbers.
Use direct map if available in linux_kmap.

Yields 20% increase in glxgears framerate.
Use device_lookup() to locate device instances
Lock irq_lock around i915_error_wake_up in i915_error_work_func.