doc: add new KNI features to release notes

doc: add new KNI features to release notes

Add the new module parameter for the KNI kernel module, the new command
line flag for the KNI sample application, and the new API function
'rte_kni_update_link()' to the release note.

Fixes: c6fd54f28c24 ("kni: add function to set link state on kernel interface")
Fixes: 89397a01ce4a ("kni: set default carrier state of interface")
Fixes: 724beb913b44 ("examples/kni: monitor and update link state continually")

Signed-off-by: Dan Gora <dg@adax.com>
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>