msm: perf: initialise krait perf L2 counter enables

Clear the L2 counter enables at initialisation.
They are undefined out of reset.

Change-Id: I957106012625ae09efec47d4f657381963d87a5a
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>
Signed-off-by: Mekala Natarajan <mekalan@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
msm: perf: clean up duplicate constraint events