pcie_imx: Update header to describe it as a legacy driver

Since now we have the modern pcie_dw_imx.c driver for iMX SoCs,
encourage people to switch to that for any further new iMX SoC support
or even for the older iMX6 SoCs too.

Suggested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Marek Vasut <marex@denx.de>
1 file changed