crypto: msm: check potential integer overflow

According to the specification of AEAD, AEAD request crypt length is
not a fixed maximum and associated length is also same. This could
lead to potential integer overflow, thus allocating less memory. So
we need to check potential integer overflow on AEAD request length.

CRs-Fixed: 726872
Change-Id: Ie7708000bfd8c57e2fba8e02230a7ce9cdc9634c
Signed-off-by: William Clark <wclark@codeaurora.org>