ultrahdr: do not select less accurate integer method during dct

At high quality setting, less accurate integer method can have
larger psnr drops. Switch to default setting

Bug: 286617381
Test: ./libultrahdr_app -p inp_p010.yuv -y inp_420p.yuv -w 1920 -h 1080 -o 0

Change-Id: Ide126b87262e1c9a20edca7873b6ca27fc52b2cb