kernel: make SND_COMPRESS_OFFLOAD symbol visible for selection (#13193)

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36091 3c298f89-4303-0410-b956-a3cf2f4a3e73