crypto: msm: Add support for setting XTS data unit size

Based on the context flags set by client, set XTS_DU_SIZE
register to sector size of 1KB, or the actual total length
of the packet.

Change-Id: Id461a27013f99301c3ca9e714f397f33c3f6ba03
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>