Add a basic debug UART support

This commit add support of the UART debug output. The code is very
platform specific and would work only on STM3210C-EVAL
devkit(something that should be definitely fixed in the future)

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Remove leftover code

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>