clk: stm32mp1: merge 'clk-hsi-div' and 'ck_hsi' into one clock

This patch is to prepare STM32MP1 clocks in trusted mode.
This Merge will facilitate to have a more coherent clock tree
in no trusted / trusted world.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Link: https://lore.kernel.org/r/20210617051814.12018-2-gabriel.fernandez@foss.st.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>