drm/exynos: add vm_ops to specific gem mmaper
drm/exynos: add vm_ops to specific gem mmaper

Changelog v3:
use drm_file's file object instead of gem object's
- gem object's file represents the shmem storage so
  process-unique file object should be used instead.

Changelog v2:
call mutex_lock before drm_vm_open_locked is called.

Changelog v1:
This patch makes it takes a reference to gem object when
specific gem mmap is requested. For this, it sets
dev->driver->gem_vm_ops to vma->vm_ops.

And this patch is based on exynos-drm-next-iommu branch of
	git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos

Signed-off-by: Inki Dae <bae4a7a27bbc965064e97edd6e179ac4979db440@samsung.com>
Signed-off-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas