[NUCLEO_F302R8]

There exists an inconsistency between official STM schematic of Nucleo
boards and the existing hardware. Each board should have an 8MHz
external clock source. That is not the case. At some boards the solder
jumper is existing and with that the external clock source. At some
other boards the solder jumper is not available. The Nucleo_F302 should
run with 72MHz but that is only possible with an external clock source.
Because of a missing solder jumper it runs only with the internal clock
source, and that's why only with 64MHz.