cpufreq: Remove ARCH_KIRKWOOD dependency

mach-kirkwood has been removed, now that kirkwood lives in mach-mvebu.
ARCH_MVEBU is sufficient.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Link: https://lkml.kernel.org/r/1409417172-6846-8-git-send-email-andrew@lunn.ch


Signed-off-by: Jason Cooper <jason@lakedaemon.net>