dt-bindings: phy: mediatek: dsi-phy: modify compatible dependence

dt-bindings: phy: mediatek: dsi-phy: modify compatible dependence

mt7623-mipi-tx is compatible to mt2701-mipi-tx, and use
"mediatek,mt2701-mipi-tx" instead on MT7623, so modify
the compatible items to make dependence clear.

Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20210316092232.9806-2-chunfeng.yun@mediatek.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>