crypto: msm: Reset encr_cfg before auth operation

Before starting any  authentication operation we need to
ensure all encryption related configurations are invalid.
This is done by setting the encryption config register to 0.

Change-Id: I294834c78a46063bb3c564cdebcaafbc5f846952
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>