lib: arm_ffa: Add support for sending FFA_MSG_SEND_DIRECT_REQ2 requests am: 83d6fe5207

Original change: https://android-review.googlesource.com/c/trusty/lk/trusty/+/3462916

Change-Id: I615fbf2c6443398462d10ca70a82947cf3cdd8ab
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>