phy: phy-mtk-tphy: set utmi 0 register in init() ops

No need repeat to clear utmi 0 register in ->power_on() and
->power_off(), just do it in ->init()

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220914060746.10004-6-chunfeng.yun@mediatek.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>