Fix non-portable definition of CryptoPlugin::SubSample

bug: 16016106
Change-Id: I76514b2e7a28c86a0b0b311af575ca9dfc9471a9
diff --git a/include/media/hardware/CryptoAPI.h b/include/media/hardware/CryptoAPI.h
index 44a0040..59ae795 100644
--- a/include/media/hardware/CryptoAPI.h
+++ b/include/media/hardware/CryptoAPI.h
@@ -51,8 +51,8 @@
     };
 
     struct SubSample {
-        size_t mNumBytesOfClearData;
-        size_t mNumBytesOfEncryptedData;
+        uint32_t mNumBytesOfClearData;
+        uint32_t mNumBytesOfEncryptedData;
     };
 
     CryptoPlugin() {}