Revert "core_ctl: Add a kernel parameter to disable core_ctl"

Now that the support to enable/disable core control from sysfs
node available, kernel parameter isn't needed anymore.
So, revert 'commit 1aeb977e ("core_ctl: Add a kernel
parameter to disable core_ctl")' to drop kernel parameter
support and follow up patches need core control to populate
cluster stats to enable/disable core control.

Change-Id: Ifbe59c288bd405a376c14e9dfda49a6042674068
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>