cpufreq: Kconfig: Move CPU_FREQ_MSM from arch to cpufreq

drivers/cpufreq already has Kconfig.arm for vendor specific Kconfig
definition. Move CPU_FREQ_MSM from arch/arm/Kconfig to
drivers/cpufreq/Kconfig.arm so that ARM64 can share the same
configuration option.

Change-Id: I68a0a170cd676541ecba325722e0d0e0fe15aefc
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>