ARM: tegra: boot with performance freq governor

ARM: tegra: boot with performance freq governor

 - Set the CPU frequency governor to performance, once
   DVFS and clock initialization is done
 - Leave the initial CPU frequency governor to userspace,
   as initially CL-DVFS is not ready, thus the system is
   already at the highest frequency

Bug 1458081

Change-Id: I29f3a023513e87d3c7411bda6daaf4000517fc72
Signed-off-by: Sang-Hun Lee <sanlee@nvidia.com>
Reviewed-on: http://git-master/r/384138
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Aleksandr Frid <afrid@nvidia.com>
Reviewed-by: Mitch Luban <mluban@nvidia.com>