forked from Imagelibrary/rtems
## spec/stm32h7: Default nucleo-h755zi BSP to build for CORE_M7 Some of the STM32H7 parts have a secondary Cortex M4 core included and require the user to select which core they are compiling for. The `arm/nucleo-h755zi` BSP was lacking a default core selection, causing the BSP to fail to build with the default options selected. This PR changes the default option to select the larger Cortex M7 core by default.