Implement emulated RPMB backend

The backend uses a memory allocated buffer for storing data and it
emulates all the necessary data frame checks which makes it ideal for
testing in host environment.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I18600ad6ccf969e75b43029a04daf8c3524aec59
3 files changed