mfd: intel-lpss: Add support for MacBookPro16,2 ICL-N UART

Added 8086:38a8 to the intel_lpss_pci driver. It is an Intel Ice Lake
PCH-N UART controler present on the MacBookPro16,2.

Signed-off-by: Orlando Chamberlain <redecorating@protonmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20211002111449.12674-1-redecorating@protonmail.com