Initial contribution of the euart driver by Accenture.
Known issues
============
When the FIFO is enabled we seem to get some dropped characters, as a temporary workaround a polling mode is enabled.
33bd282ab944036070609a35154c4ec6b5620e77 PDK_3.0.b
7cd561e7f75e5756a46b8c59364dd9b285c68f50 PDK_3.0.c
dc9b4bd57f72022c45b4dd06c087b7b44a46c697 PDK_3.0.d
344fc5a7c938446f43f8e0429cb3fea76bb24df8 PDK_3.0.e