defconfig: msm8916: Enable CONFIG_FREE_PAGES_RDONLY

Enable CONFIG_FREE_PAGES_RDONLY to debug scribbling
of drivers on free pages. We do not need to enable
FORCE_PAGES as FREE_PAGES_RDONLY implicitly selects
it. This is intended to be used as a debugging feature
and should NOT be used for performance testing.

Change-Id: Ic9f9ee735eefa273f886fe5de287088505bf9a76
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>