libutee: reset state after TEE_DigestDoFinal()
libutee: reset state after TEE_DigestDoFinal()

As per GlobalPlatform Internal API Specifications v1.0 and v1.1,
section 6.3.2 TEE_DigestDoFinal: "Afterwards the Message Digest
operation is reset [to initial state] and can be reused" (the words
in square brackets are in v1.1 only).

Note that other TEE_xxxFinal() functions are not modified because
the specifications state that the application shall panic if "the
operation has not been started yet with TEE_[xxx]Init() or has already
been finalized."

Signed-off-by: Jerome Forissier <ced78d268b4c9a0a20a59a9feeebd2ad90da03d3@linaro.org>
Reviewed-by: Pascal Brand <0b55292d2562685bad4ce52d64f802e8f1cd299e@linaro.org>

pascal-brand-st-dev/optee_os,matt2048/optee_os,Microsoft/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,chshxi1989/optee_os,matt2048/optee_os,Microsoft/optee_os,chshxi1989/optee_os,cedric-chaumont-st-dev/optee_os,matt2048/optee_os,Microsoft/optee_os,cedric-chaumont-st-dev/optee_os,matt2048/optee_os,pascal-brand-st-dev/optee_os,chshxi1989/optee_os,Microsoft/optee_os,cedric-chaumont-st-dev/optee_os,pascal-brand-st-dev/optee_os,chshxi1989/optee_os,cedric-chaumont-st-dev/optee_os,Microsoft/optee_os,chshxi1989/optee_os