H7: Override PLL1 frequency for revision Y devices.
H7: Override PLL1 frequency for revision Y devices.

* Some rev Y devices fail with 480MHz overclocking. Override PLL settings
to set a maximum frequency of 400MHz CPU 200MHz Bus for rev Y devices.

kwagyeman/openmv,kwagyeman/openmv,openmv/openmv,iabdalkader/openmv,kwagyeman/openmv,openmv/openmv,kwagyeman/openmv,iabdalkader/openmv,openmv/openmv,iabdalkader/openmv,iabdalkader/openmv,openmv/openmv