Also ensure that it uses the highest supported value, and
abort if the value is not above a minimum threshold.
Test: Tested against the curent kernel (maximum value of 2,
set to 0 by the kernel initially) and against a
modified kernel (maximum value of 4, set to 4 by the
kernel initially)
Bug: 30368199
Change-Id: I608db577258b68b390ffe96f452e1f7c0bc9ad8a