Add ATmega328P Xplained Mini board. The board is an official
development kit from MCHP based on the Arduino UNO, reduced
hardware, with a xplainedmini debugger and CDC ACM serial
converter.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
This add an implementation of PBKDF2 using sha256 hmac. Only one derived
key length is supported (32) though it should not be hard to extend it.
The testing is done with both random (with fixed seed) vectors amd vectors
from rfc7914.
