arm64: cputype: Add comments about Qualcomm Kryo 5XX and 6XX cores

arm64: cputype: Add comments about Qualcomm Kryo 5XX and 6XX cores

As tested on one example of a Qualcomm Kryo 5XX CPU [1] and one
example of a Qualcomm Kryo 6XX CPU [2], we don't need any extra MIDR
definitions for the cores in those processors. Add comments to make it
clear that these IDs weren't forgotten and just aren't needed.

[1] https://lore.kernel.org/r/l5rqbbxn6hktlcxooolkvi5n3arkht6zzhrvdjf6kis322nsup@5hsrak4cgteq/
[2] https://lore.kernel.org/r/tx7vtur7yea6ruefrkpkccqptahgmxnsrudwdz5uzcfxnng25b@afrr5bmdk2xa/

Suggested-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Trilok Soni <quic_tsoni@quicinc.com>
Link: https://lore.kernel.org/r/20241219131107.v3.2.I520dfa10ad9f598581c2591d631aa6e9e26f7603@changeid
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>