defconfig: arm64: Enable DM REQ for msmtitanium

Enable DM req crypt driver, which requires for hardware based disk
encryption for msmtitanium.

Change-Id: I10ceee6a2eadcfa2446c96fff9a05d8891ded224
Signed-off-by: Mallikarjuna Reddy Amireddy <mamire@codeaurora.org>