sw64: reorganize CPU_FREQ related config

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I56OLG



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Move CPU_FREQ related arch config to drivers/cpufreq/Kconfig and use
'source' to add it to arch/sw_64/Kconfig instead of copy everything we
need.

Signed-off-by: Mao Minkai <maominkai@wxiat.com>
Reviewed-by: He Sheng <hesheng@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>