linux-yocto.inc: ensure do_kernel_link_images runs before do_strip

linux-yocto.inc: ensure do_kernel_link_images runs before do_strip

If the do_kernel_link_images task is enabled, then it needs to run
before do_strip. The addtask statement for do_strip makes that
explicit. For consistency, make it explicit in the addtask statement
for do_kernel_link_images too.

(From OE-Core rev: 1296cc0538efe64d666868fd28c5b195ec9c08ff)

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>