arm64: Enable Arm64 858921 errata on kryo2xx gold cores

Add the kryo2xx gold cores to the list of CPUs that need
to have Arm64 858921 errata.

Change-Id: I2f3d59a39c95784f8760705e3a02fdeb8dbdb27d
Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org>
[cchidipu@codeaurora.org: resolve trivial merge conflicts]
[cchidipu@codeaurora.org: Update midrs in arm64_workaround_858921_cpus]
Signed-off-by: Chandra Sai Chidipudi <cchidipu@codeaurora.org>