license_image.bbclass: fix missing recipeinfo on self

Resolve a build bug where image recipes with a do_deploy task will fail.

If the image recipe inheriting license_image.bbclass has a deploy task, then
the function get_deployed_dependencies will add itself to the list of recipes
to get license information for.

However, image recipes don't generally deploy license info so this results in
an error.

File: '/nvme/poky/meta/classes/license_image.bbclass', lineno: 192, function: license_deployed_manifest
...
Exception: FileNotFoundError: [Errno 2] No such file or directory: '/nvme/poky/build/tmp/deploy/licenses/core-image-minimal/recipeinfo'

Add a corner case to exclude the originating image recipe from the list of
dependencies to check.

Signed-off-by: Michael Ho <Michael.Ho@bmw.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 13fb39e4)
Signed-off-by: Steve Sakoman <steve@sakoman.com>