msm: defconfig: Enable CONFIG_ARM_DECOMPRESSOR_LIMIT

Set flag CONFIG_ARM_DECOMPRESSOR_LIMIT to 50MB size to limit
the memory to be mapped by decompressor with read, write
and execute permissions to avoid speculative prefetch.

Change-Id: If1ea154dac7274491052ec13efaecaab00cce01f
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>