init: disable watermark_boost feature

In newer kernel, it introduces watermark boost feature
to enhance memory fragmentation problems. This feature
will dynamically boost/down watermark level which conflicts
with LMKD assumption and causing LMKD not to work properly.
Disabling this feature first until we address it.

Bug: 189938926
Test: check vm parameter.
Signed-off-by: Martin Liu <liumartin@google.com>
Change-Id: I6db5163f843f1129080bb944df7cbb8c799a58e0