serial: core: Remove unused PORT_* definitions

serial: core: Remove unused PORT_* definitions

For the last couple of years Linux kernel got rid of a few architectures
and many platforms. Hence some PORT_* definitions in the serial_core.h
become unused and redundant. Remove them for good.

Removed IDs are checked for users against Debian Code Search engine.
Hence safe to remove as there are no consumers found (only providers).

While at it, add a note about 0-13, that are defined in the other file.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230821083857.1065282-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>