ANDROID: cuttlefish_defconfig: Enable blk-crypto fallback

Enable blk-crypto's kernel crypto API fallback, so that devices
without inline encryption hardware can continue to use the inlinecrypt
mount option and have file content crypto handled by the block layer.

Bug: 137270441
Test: xfstests, cuttlefish boot and stress test, pixel 4 boot and stress
      test
Change-Id: I26376479ee38259b8c35732cb3a1d7e15f9b05a3
Signed-off-by: Satya Tangirala <satyat@google.com>