Convert hasher to interface and remove spihash64

src/base/hash/hasher/siphash.h

@@ -49,8 +49,8 @@ typedef struct WpSipHasherData {
 })
 #endif
 
+WpHasher   wpSipHasher(WpSipHasherData *data);
 WpU128Hash wpSipHasher128(WpU8Stream *bytes, void *hasher_io);
-u64        wpSipHasher64(WpU8Stream *bytes, void *hasher_io);
 
 #ifdef WP_PLATFORM_CPP
 END_C_LINKAGE