Wait for Gen2 training with readl_poll_timeout(), and simplify the hardware
assert logical by merging it into a new mtk_pcie_startup_port() interface.
Signed-off-by: NRyder Lee <ryder.lee@mediatek.com>
Signed-off-by: NHonghui Zhang <honghui.zhang@mediatek.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>