drm/amdgpu: use amdgpu_bo_create_user() for when possible

Use amdgpu_bo_create_user() for all the BO allocations for
ttm_bo_type_device type.

v2: include amdgpu_amdkfd_alloc_gws() as well it calls amdgpu_bo_create()
    for  ttm_bo_type_device

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>