power: bcl: Support selective core frequency mitigation

Add support for frequency core control list in devicetree.
This is used to generate a frequency core control mask.
This is required since it will provide flexibility to control
which core need frequency mitigation on a target under
BCL condition.

Change-Id: Ib4bb12c47dcddd0021302c9ecc036f419a532bb5
Signed-off-by: Shiju Mathew <shijum@codeaurora.org>