Added bkpt before printf() in assert handler.
Added bkpt before printf() in assert handler.

- Since printf() outputs via the UART at a slow baud rate using polling,
  it can cause all sorts of issues with the OS, thus causing another
  assertion failure before hitting the bkpt of the original assertion.

flit/modular,flit/modular,flit/modular,flit/modular,flit/modular