gator: update to 5.18 release
gator: update to 5.18 release

 * drop AUTOREV
 * bump PV to 5.18+
 * drop PR
 * fix style issues

Change-Id: I228644bb6d7431cff900035fcbb6f11b850070e6
Signed-off-by: Fathi Boudra <7cd6e55cc07a66bc71d7901a4cddfe6c22aab659@linaro.org>

linaro-home/meta-linaro,xleng/meta-linaro,xleng/meta-linaro,linaro-home/meta-linaro,xleng/meta-linaro,xleng/meta-linaro,linaro-home/meta-linaro,linaro-home/meta-linaro,xleng/meta-linaro,linaro-home/meta-linaro,linaro-home/meta-linaro