kernel: add a small xfrm related performance optimization

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41950 3c298f89-4303-0410-b956-a3cf2f4a3e73
kernel: when using --gc-sections, add --sort-section=name to get a more stable sorting order

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41951 3c298f89-4303-0410-b956-a3cf2f4a3e73