LF-3755 PCI: imx: move the compliance tests mode enable to command line

commit 5a8431973bd0958c0c9bd410f7f18caedb9d43bd from
git://source.codeaurora.org/external/qoriq/qoriq-components/linux



To avoid the kernel rebuild after change the menuconfig, move the i.MX
PCIe compliance tests mode enable to kernel command line.
Use the "pcie_cz_enabled=yes" to enable the compliance tests mode.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Meng Li <Meng.Li@windriver.com>