Fix unaligned access error in oemcrypto_ref

Merge from Widevine repo of http://go/wvgerrit/131247

test: opk_all_tests with go/wvgerrit/129283
bug: 193817424
Change-Id: I4dac732a7d2dcbbcdac2d9b445dc87ef71a35349

libwvdrmengine/oemcrypto/ref/src/oemcrypto_session.cpp

@@ -7,6 +7,7 @@
 #include "oemcrypto_session.h"
 
 #include <assert.h>
+
 #include <string.h>
 #include <algorithm>
 #include <iostream>
@@ -1858,7 +1859,7 @@ OEMCryptoResult SessionContext::SetDecryptHash(uint32_t frame_number,
   }
   compute_hash_ = true;
   current_frame_number_ = frame_number;
-  given_hash_ = *reinterpret_cast<const uint32_t*>(hash);
+  memcpy(&given_hash_, hash, sizeof(uint32_t));
   return OEMCrypto_SUCCESS;
 }