drm/amdgpu: use a 64bit interval tree for VM management v2

This only makes a difference for 32-bit systems. The idea is to have a
fixed virtual address space size with 4-level page tables and to
minimize differences between 32 and 64-bit systems.

v2: Update commit message.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
index 0b92dd0..2ca09f1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
@@ -741,10 +741,10 @@
 
 	start = amdgpu_bo_gpu_offset(bo);
 
-	end = (mapping->it.last + 1 - mapping->it.start);
+	end = (mapping->last + 1 - mapping->start);
 	end = end * AMDGPU_GPU_PAGE_SIZE + start;
 
-	addr -= ((uint64_t)mapping->it.start) * AMDGPU_GPU_PAGE_SIZE;
+	addr -= mapping->start * AMDGPU_GPU_PAGE_SIZE;
 	start += addr;
 
 	amdgpu_set_ib_value(ctx->parser, ctx->ib_idx, ctx->data0,