clk: stm32mp13: add safe mux management

Some muxes need to set a the safe position when clock is off.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Link: https://lore.kernel.org/r/20220516070600.7692-12-gabriel.fernandez@foss.st.com


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