arm64: Add KRYO{3,4}XX silver CPU cores to SSB safelist

QCOM KRYO{3,4}XX silver/LITTLE CPU cores are based on
Cortex-A55 and are SSB safe, hence add them to SSB
safelist -> arm64_ssb_cpus[].

Reported-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200625103123.7240-1-saiprakash.ranjan@codeaurora.org
Signed-off-by: Will Deacon <will@kernel.org>