drver:soc:llcc_perfmon: qdss clk node control

qdss clock needs to be enabled on llcc_perfmon counter to function.
Enable/disable clock on Start/Stop llcc_perfmon commands.

Change-Id: I73a13b7de023187b3fbdf256be7594502e46f4f9
Signed-off-by: Avinash Philip <avinashp@codeaurora.org>