MLK-18953 PCI: imx: fix the building warning

MLK-18953 PCI: imx: fix the building warning

- warning: ‘retries’ may be used uninitialized in this function
- WARNING: vmlinux.o(.data+0x5d2d8): Section mismatch in reference from the
variable imx_pcie_driver to the function .init.text:imx_pcie_probe()

The variable imx_pcie_driver references the function __init
imx_pcie_probe().
If the reference is valid then annotate the variable with
__init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Signed-off-by: Jason Liu <jason.hui.liu@nxp.com>
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
rebase on v4.19
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>