MBED_STRUCT_STATIC_ASSERT: Use standard C++11/C11
MBED_STRUCT_STATIC_ASSERT: Use standard C++11/C11

If available, we can use standard static_assert.

mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,kjbracey-arm/mbed,andcor02/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,mbedmicro/mbed,mbedmicro/mbed,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os