arm: tegra: thermal: register balanced throttle cdev

arm: tegra: thermal: register balanced throttle cdev

Register balanced throttle tables with tegra-balanced-throttle
sub-layer in thermal. Whether it will be made available on a device or
not will be determined in platform init code by a routine that binds
to its thermal sensor.

Change-Id: I9e403b718e37e19c5376d0177179c135c0b160d0
Signed-off-by: Diwakar Tundlam <dtundlam@nvidia.com>
Reviewed-on: http://git-master/r/417897