msm: correct nohlt behavior

Correct the values being passed from debugfs/nohlt.
Now writing 1 to nohlt increments it and writing
0 decrements it, as expected.

Change-Id: I34b07e1facc8fcf2294fd629561d69ea83d8475d
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>