drm/amdgpu: partially revert "drm/amdgpu: fix VM_CONTEXT*_PAGE_TABLE_END_ADDR" v2

The gtt_end is already inclusive, we don't need to subtract one here.

v2 (chk): keep the fix for the VM code, cause here it really applies.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Anatoli Antonovitch <anatoli.antonovitch@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>