coresight: fix spinlock corruption issue

Spinlock corruption is observed on secure fuse
enabled devices due to invalid data present in
etmdrvdata array. Initialise the array
to fix the issue.

Change-Id: Ib16e3c3f6dc7d194af4eeca6f58c78483af71482
CRs-fixed: 1084892
Signed-off-by: Amey Telawane <ameyt@codeaurora.org>