clk: tegra: Fix disable unused for clocks sharing enable bit

clk: tegra: Fix disable unused for clocks sharing enable bit

In case 2 clocks share an enable bit and one of them is enabled by a
driver and the other one is not, CCF will think it's enabled because it
will only look at the HW state. Therefore it will disable the clock and
thus also disable the other clock which was enabled. Solve this by
reading the initial state of the enable bit and incrementing the
refcount if it's set.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>