Move the phy_power_on() to host_init from imx6_pcie_clk_enable().

Move the phy_init() to host_init from imx6_pcie_deassert_core_reset().

Refine the error handling in imx6_pcie_host_init() accordingly.

Link: https://lore.kernel.org/r/1657783869-19194-15-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>