license: Rework INCOMPATIBLE_LICENSE wildcard handling

The current wildcard handling is badly documented and inconsistently
used and understood.

Forcing users to have to use "GPL-3.0-only GPL-3.0-or-later" whilst
explict is not very user friendly. Equally, using the current wildcards
is ambigious. This supports pre-defined expansions only and at least makes
it clear what GPL-3.0* means (it doesn't include the exception licenses).

This is hopefully an acceptable compromise between literal meaning and
having something usable.

Non-SPDX forms of license in this field have been dropped and errors are
shown for unsupported expansions and unsupported old style license terms.

Users need to carefully consider how to migrate to the new syntax but
the meaning should be well defined and clear from here forward.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>