redundant xf86-video-intel patches

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

We have local patches to use
1) drmIoctl instead of do_ioctl
2) drmMap   instead of mmap

1) The only difference between drmIoctl and do_ioctl is that do_ioctl calls
   sched_yield() if ioctl returns EAGAIN. Why is calling sched_yield() a
   bad idea?

   The sched_yield() call was added upstream in:

   Author: Chris Wilson <chris%chris-wilson.co.uk@localhost>
   Date:   Mon Jan 20 09:32:50 2014 +0000

    sna: Yield the processor if the kernel reports EAGAIN
    
    An artifact of our kernel/userspace interaction is that under certain
    circumstances the kernel will report EAGAIN in order for it to have CPU
    time to run its own workqueues before it can process the userspace
    request. We can be cooperative and yield ourselves rather than busy-spin
    waiting for the scheduler to demote us.

2)  Again, anyone remember what lead to us thinking that __kgem_bo_size()
    is doing the wrong thing?

    drmMap:
      pagesize_mask = getpagesize() - 1;
      size = (size + pagesize_mask) & ~pagesize_mask;
    mmap with call to bytes() => __kgem_bo_size():
      return PAGE_SIZE * bo->size.pages.count;

A poor experiment is that without those two changes, I can run
intel_drv.so on NetBSD-current/amd64 on a Sandy Bridge, which
suggests that they might no longer be necessary.

It is a poor experiment in the sense that that is probably a well
tested configuration... 32-bit and old intel would be better.

Cheers,

Patrick