perfmon: properly unmap mmapped pages
perfmon: properly unmap mmapped pages

Add missing array index so that actual mmapped pages are unmpapped
instead of attempting to unmap array holding those pages.

Type: fix
Signed-off-by: Klement Sekera <b8003f27414ca85c37624503b7b4e8f8c829bb4d@cisco.com>
Change-Id: Ib8709cce1bcbfb505307c140266834b284af796c

FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp