ARM: tegra: Move cluster switch code

ARM: tegra: Move cluster switch code

Moved out the cluster switch code to a more appriopriate location as
cluster switch doesn't have a direct dependency on CPU_FREQ. The callers
of cluster_switch will now have to ensure proper locking is done on
their end.

Also make sure clk rates are in the correct range on a cluster switch
request.

Change-Id: I6d90d0aae239cff0566714b9c34db04304aa63ca
Signed-off-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-on: http://git-master/r/539057
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>