lmkd: change defaults to disable event upgrade/downgrade logic

(cherry pick from commit ad2fd915)

vmpressure upgrade/downgrade logic based on swap utilization works well
for low memory devices because of a small swap size, however for high
performance devices this measure is not a good indication of the memory
pressure because of large swap resources. This change sets the default
levels to disable upgrade/downgrade logic by default and each device
can set these properties appropriately.

Bug: 63631020
Test: alloc-stress

Change-Id: Ifd4fbd4d6bb3e82f0f87b029df94934f1e7b1c9c
Merged-In: Ifd4fbd4d6bb3e82f0f87b029df94934f1e7b1c9c
Signed-off-by: Suren Baghdasaryan <surenb@google.com>