drm/msm/hdcp2.2: return proper error code on aux failures

In case of aux read/write failures during hdcp message exchange
between source and sink, return with error so that hdcp state
machine can take corrective action.

CRs-Fixed: 2292768
Change-Id: I5df7a8d77796784b48c09436004aa7ec93a51283
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>