drm/gem: fix mmap vma size calculations
drm/gem: fix mmap vma size calculations

The VMA manager is page-size based so drm_vma_node_size() returns the size
in pages. However, drm_gem_mmap_obj() requires the size in bytes. Apply
PAGE_SHIFT so we no longer get EINVAL during mmaps due to too small
buffers.

This bug was introduced in commit:
  0de23977cfeb5b357ec884ba15417ae118ff9e9b
  "drm/gem: convert to new unified vma manager"

Fixes i915 gtt mmap failure reported by Sedat Dilek in:
  Re: linux-next: Tree for Jul 25 [ call-trace: drm | drm-intel related? ]

Cc: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>
Cc: Chris Wilson <711c73f64afdce07b7e38039a96d2224209e9a6c@chris-wilson.co.uk>
Signed-off-by: David Herrmann <fb53b2ddb8d141e0cb39d7c67c2f81b6bc2eb0f7@gmail.com>
Reported-by: Sedat Dilek <4946ef7dd8f3b21b6f8e2f51ee1d2e36059c35a6@gmail.com>
Tested-by: Sedat Dilek <4946ef7dd8f3b21b6f8e2f51ee1d2e36059c35a6@gmail.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs