defconfig: msm8916-512: Enable CONFIG_BALANCE_ANON_FILE_RECLAIM

CONFIG_BALANCE_ANON_FILE_RECLAIM option treats anonymous and
file backed pages equally while memory reclaim. This makes
memory reclaim better, offering more headroom for
applications. Enable it on msm8916 512MB configurations.

CRs-fixed: 675289
Change-Id: Id043e87c29e44f77fd7fc7c3163f759d52eb7090
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>