Perf: Fix event type mask

Adding mode exclusion to Krait P2 (commit: 48c15105)
introduced a subtle bug to 8660 perf code where, the event mask
would only keep the lower byte of info sent from userspace.
This would configure the PMU's to count the wrong event in
some cases.

Fix the event mask so that all the required info is parsed
and the PMU's are configured correctly.

Change-Id: Id9afd3d743f6256df96c55191ebd68503d2cb05f
Signed-off-by: Ashwin Chaugule <ashwinc@codeaurora.org>