smb3: fix signing verification of large reads

smb3: fix signing verification of large reads

[ Upstream commit 46f17d17687e8140f2e4e517d7dfa65e62fcc5f4 ]

Code cleanup in the 5.1 kernel changed the array
passed into signing verification on large reads leading
to warning messages being logged when copying files to local
systems from remote.

   SMB signature verification returned error = -5

This changeset fixes verification of SMB3 signatures of large
reads.

Suggested-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>