clk: stm32mp1: remove intermediate pll clocks

clk: stm32mp1: remove intermediate pll clocks

This patch is to prepare STM32MP1 clocks in trusted mode.
Integrate the mux clock into pll clock will facilitate to have a more
coherent clock tree in no trusted / trusted mode.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Link: https://lore.kernel.org/r/20210617051814.12018-4-gabriel.fernandez@foss.st.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>