qcdev: Check the digest length during the SHA operations

Check the digest length to avoid buffer overflow while
doing the SHA operations.

Bug: 36591162
CRs-Fixed: 2045061
Change-Id: I4d3fb20723f59e905a672edaf84ee5d0865905b1
Signed-off-by: Brahmaji K <bkomma@codeaurora.org>
Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>