Fix copypasta in documentation of an error case

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index a17bfc2..c2a2770 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -1170,8 +1170,7 @@
  *
  * \return              The tag length specified by the input algorithm.
  * \return              Unspecified if \p alg is not a supported
- *                      AEAD algorithm or if \p tag_length is not valid
- *                      for the specified AEAD algorithm.
+ *                      AEAD algorithm.
  */
 #define PSA_ALG_AEAD_GET_TAG_LENGTH(aead_alg)                           \
     (((aead_alg) & PSA_ALG_AEAD_TAG_LENGTH_MASK) >>                     \