defconfig: msm8916: Align 512MB with 1GB defconfig

Update and align both debug and perf defconfigs for 512MB
msm8916 platforms with their equivalent 1GB defconfigs.

Both defconfigs should be exaclty aligned except for the
specific features which are chosen to be disabled/enabled on
512MB platforms.

CRs-fixed: 664298
Change-Id: Ib507955c1beb7cac2b18b7b683e23bef86ab42e4
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>