phy: phy-mtk-tphy: fix NULL point of chip bank

Chip bank of version-1 is initialized as NULL, but it's used
by pcie_phy_instance_power_on/off(), so assign it a right
address.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>