[ARM]: tegra: add a clock entry for h/w statistics monitor

[ARM]: tegra: add a clock entry for h/w statistics monitor

Add a PERIPH_CLK for hardware statistics monitor of Tegra2.
This will enable to call standard clk* APIs to enable/disable/reset
the statistics monitor.

Change-Id: Ic7050ba8af6c7ed39744b65dfb953ba029deb2ea
Reviewed-on: http://git-master/r/17674
Reviewed-by: Varun Wadekar <vwadekar@nvidia.com>
Reviewed-by: Aleksandr Frid <afrid@nvidia.com>
Reviewed-by: Amit Kamath <akamath@nvidia.com>
Tested-by: Mayuresh Kulkarni <mkulkarni@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Reviewed-by: Varun Colbert <vcolbert@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>