[U-Boot] SPDX-License-Identifier on new files

[D Rambo]

Is there a policy that new source files upstreamed to u-boot contain
registered SPDX license identifiers? I see that there are still about 1900
source files that have no SPDX identifier, and about 6000 that do. The
reason I'm asking is that our company has a dual license (for GPL2.0 or
Proprietary), and would like to know if it is possible to submit code that
has the legacy dual license first (and register/clean up SPDX later), or if
we need to do the internal legal and register the appropriate licenses with
spdx.org first before submission upstream?

Another question is related to http://spdx.org/about-spdx/faqs

       *How does one represent a file or package that is dual licensed
(i.e., a license choice)?*

       SPDX license information can be represented using conjunctive or
disjunctive regular expressions.  For example, a file that is dual licensed
under either the GPL-2.0 or MIT would be represented using the following
disjunctive expression: (GPL-2.0 *or* MIT).

So my question is whether a dual license can be registered with spdx or is
it necessary to split the dual license and show the "or" condition above.
In other words, is the "or" parsing critical to license clearing reports?

Thanks.