Enhance the cast from uint32_t to uint32_t* by intermediate casting through uintptr_t...

Enhance the cast from uint32_t to uint32_t* by intermediate casting through uintptr_t in __NVIC_SetVector/GetVector

This allows the header to be compiled on a non-32bit architecture
without the warning int-to-pointer-cast. It is also a clean approach
when turning a uint32_t value to a pointer and should not add any
additional cycles on a 32bit architecture.