drm/amd/display: Allocate DCN35 clock table transfer buffers in GART

[Why]
Request from PMFW to use GART for clock table transfer tables as
framebuffer is being deprecated on APU.

[How]
Switch over to GART via the allocation flag.

Reviewed-by: Sung joon Kim <sungjoon.kim@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>