lpm-workarounds: Prevent to enable clock_gating more than once

Prevent attempts to enable dynamic_clock_gating more than once.
If it is enabled more than once performance cores are getting
hotplugged due to mitigation request made.

Change-Id: If91e6f6999a3b917b3ff04cf82e46471211fe478
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>