drm/radeon: Implement mmap as GEM object function

Moving the driver-specific mmap code into a GEM object function allows
for using DRM helpers for various mmap callbacks.

This change also allows to support prime-based mmap via DRM's helper
drm_gem_prime_mmap().

Permission checks are implemented by drm_gem_mmap(), with an additional
check for radeon_ttm_tt_has_userptr() in the GEM object function. The
function radeon_verify_access() is now unused and has thus been removed.

As a side effect, radeon_ttm_vm_ops and radeon_ttm_fault() are now
implemented in amdgpu's GEM code.

v3:
* remove unnecessary checks from mmap (Christian)
v2:
* rename radeon_ttm_vm_ops and radeon_ttm_fault() to
radeon_gem_vm_ops and radeon_gem_fault() (Christian)
* fix commit description (Alex)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210525151055.8174-4-tzimmermann@suse.de

drm/radeon/radeon_drv: Move 'radeon_mmap()'s prototype to shared header

Fixes the following W=1 kernel build warning(s):

drivers/gpu/drm/radeon/radeon_ttm.c:931:5: warning: no previous prototype for ‘radeon_mmap’ [-Wmissing-prototypes]
931 | int radeon_mmap(struct file *filp, struct vm_area_struct *vma)
| ^~~~~~~~~~~

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Gareth Hughes <gareth@valinux.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/radeon: Move radeon_ttm{init, fini} to shared location

Fixes the following W=1 kernel build warning(s):

drivers/gpu/drm/radeon/radeon_ttm.c: At top level:
drivers/gpu/drm/radeon/radeon_ttm.c:817:5: warning: no previous prototype for ‘radeon_ttm_init’ [-Wmissing-prototypes]
817 | int radeon_ttm_init(struct radeon_device *rdev)
| ^~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/radeon_ttm.c:878:6: warning: no previous prototype for ‘radeon_ttm_fini’ [-Wmissing-prototypes]
878 | void radeon_ttm_fini(struct radeon_device *rdev)
| ^~~~~~~~~~~~~~~

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>