defconfig : 8916 : Remove debug flags for less memory footprint

The following debug flags are removed in this commit:
-CONFIG_PAGE_OWNER
-CONFIG_SLUB_DEBUG_ON
-CONFIG_SLUB_DEBUG_PANIC_ON
-CONFIG_FREE_PAGES_RDONLY
-CONFIG_KERNEL_TEXT_RDONLY

With the inclusion of these flags, memory consumption is increasing
and hence LMK kicks in early and kills applications more frequently.
Hence, remove them to make sure out of memory is not observed
frequently.

Change-Id: Id05ebeb83e5a7010fdd28768b584e8fea52d2ae6
Signed-off-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>