feat(st-clock): do not refcount on non-secure clocks in bl32

This change removes reference counting support in clock gating
implementation for clocks that rely on non-secure only RCC resources.
As RCC registers are accessed straight by non-secure world for these
clocks, secure world cannot safely store the clock state and even
disabling such clock from secure world can jeopardize the non-secure
world clock management framework and drivers.

As a consequence, for such clocks, stm32_clock_enable() forces the clock
ON without any increment of a refcount and stm32_clock_disable() does
not disable the clock.

Change-Id: I0cc159b36a25dbc8676f05edf2668ae63c640537
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
1 file changed