Revert "kernel.bbclass: run do_symlink_kernsrc before do_patch"
This reverts commit 914d8a00e34a8edf75a349da6f5978e4ed60e6d5.
Due to bug introduced for externalsrc
https://bugzilla.yoctoproject.org/show_bug.cgi?id=14044
Signed-off-by: Steve Sakoman <steve@sakoman.com>