defconfig: arm: msm: Enable CONFIG_ARM_KERNMEM_PERMS for msm8937

Enabling ARM_KERNMEM_PERMS will make kernel
memory other than kernel text as non-executable.
Also this would enable dependent config
CONFIG_DEBUG_RODATA which would help catch
attempts to change the kernel's executable code.

Change-Id: Ica0d6297fbcd4f974ba29935d4a2fca0169844bc
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>