crypto/sha256: add license file for intel code in benchmarks/

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/crypto/sha256/benchmarks/open_software_license.txt

+Copyright (c) 2012, Intel Corporation 
+
+All rights reserved. 
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met: 
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.  
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in the
+  documentation and/or other materials provided with the
+  distribution. 
+
+* Neither the name of the Intel Corporation nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission. 
+
+
+THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION ""AS IS"" AND ANY
+EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL CORPORATION OR
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.