serial: sccnxp: Using structure for each supported IC instead of switch in probe

This patch replaces switch in probe function to constant structure
for each supported IC. This makes code a bit smaller and cleaner and
helps adding DT support to the driver in the future.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>