ANDROID: KVM: arm64: Use the correct handle during ff-a transfer

Fix the handle creation when the caller is using the
fragmentation API. The returned registers w2 and w3
have a different purpose when the caller is using the
memory sharing for the fragmentation API and they are
defined in 4.1.2.4 FFA_MEM_FRAG_RX (DEN0140 FF-A 1.3):
 - w3 represent a byte offset
 - w2 part of the handle
Use the w1 and w2 to construct the handle when
fragmentation API is used and w2 and w3 when an
individual memory transaction is sent.

Bug: 269285339
Bug: 278749606
Change-Id: Ia39507653440de450048dca488c720c0af04cf58
Signed-off-by: Sebastian Ene <sebastianene@google.com>