pyrsistent is a dependency of python3-jsonschema, which is being
imported to support kernel device tree validation.
(From OE-Core rev: e25d4417bc4ca01474c74dc5bd38594bcfbe6639)
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
