cve-check: no need to depend on the fetch task

cve-check: no need to depend on the fetch task

The only part of the cve-check task which needs files is the patch
examination, and typically these patches are local so fetch isn't needed.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 2c9b3186d3b7c18cbea239ab9b06e85b7c243b54)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
(cherry picked from commit 3dc8edd6611e7ad4abcece44ca4701eda7aeff94)
Signed-off-by: Steve Sakoman <steve@sakoman.com>