ARM: tegra: clock: add DC2 to iso usage table

ARM: tegra: clock: add DC2 to iso usage table

Consider DC1 and DC2 as separate iso client.
If DC1 and DC2 are on at the same time, use lower
iso efficiency as DC is on with other client.

Bug 1320063

Change-Id: Id2060339b50899a4507df0e6dee62648a3a9bd2f
Reviewed-on: http://git-master/r/247282
(cherry picked from commit e2fba905182737c73446f5d989b22cb5d886963a)
Signed-off-by: Jihoon Bang <jbang@nvidia.com>
Reviewed-on: http://git-master/r/247251
(cherry picked from commit f6111cb1ab843c60a6265610d686deb6475b8f36)
Signed-off-by: Jihoon Bang <jbang@nvidia.com>
Reviewed-on: http://git-master/r/254364
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>