defconfig: Enable lowmemorykiller autodetect option

Recent ABI changes have made the lowmemorykiller less effective.
Enable ANDROID_LOW_MEMORY_KILLER_AUTODETECT_OOM_ADJ_VALUE to
detect when the old ABI is being used and convert it to the new
ABI.

Change-Id: If47113e5fc7706bcd6bb144c591e9935b0c5115a
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>