attempt to silence a recent ubsan warning with code reorganization

apparently, UBSAN uses the prototype of the inner inlined function
instead of the outer shell of the function.
Let's see if one indirection level is enough to fix this.

xxhash.h

@@ -6523,8 +6523,9 @@ XXH3_consumeStripes(xxh_u64* XXH_RESTRICT acc,
 #   define XXH3_STREAM_USE_STACK 1
 # endif
 #endif
-/*
- * Both XXH3_64bits_update and XXH3_128bits_update use this routine.
+/* This function accepts f_acc and f_scramble as function pointers,
+ * making it possible to implement multiple variants with different acc & scramble stages.
+ * This is notably useful to implement multiple vector variants with different intrinsics.
  */
 XXH_FORCE_INLINE XXH_errorcode
 XXH3_update(XXH3_state_t* XXH_RESTRICT const state,
@@ -6605,12 +6606,21 @@ XXH3_update(XXH3_state_t* XXH_RESTRICT const state,
     return XXH_OK;
 }
 
+/*
+ * Both XXH3_64bits_update and XXH3_128bits_update use this routine.
+ */
+static XXH_errorcode
+XXH3_update_regular(XXH_NOESCAPE XXH3_state_t* state, XXH_NOESCAPE const void* input, size_t len)
+{
+    return XXH3_update(state, (const xxh_u8*)input, len,
+                       XXH3_accumulate, XXH3_scrambleAcc);
+}
+
 /*! @ingroup XXH3_family */
 XXH_PUBLIC_API XXH_errorcode
 XXH3_64bits_update(XXH_NOESCAPE XXH3_state_t* state, XXH_NOESCAPE const void* input, size_t len)
 {
-    return XXH3_update(state, (const xxh_u8*)input, len,
-                       XXH3_accumulate, XXH3_scrambleAcc);
+    return XXH3_update_regular(state, input, len);
 }
 
 
@@ -7146,7 +7156,7 @@ XXH3_128bits_reset_withSecretandSeed(XXH_NOESCAPE XXH3_state_t* statePtr, XXH_NO
 XXH_PUBLIC_API XXH_errorcode
 XXH3_128bits_update(XXH_NOESCAPE XXH3_state_t* state, XXH_NOESCAPE const void* input, size_t len)
 {
-    return XXH3_64bits_update(state, input, len);
+    return XXH3_update_regular(state, input, len);
 }
 
 /*! @ingroup XXH3_family */