fix PSA_XXX typos detected by check_names.py

Fix the PSA_XXX typos detected by check_names.py.
PSA_WANT is actually not typo, but would cause a false negative
result. So PSA_WANT is reworded to PSA_WANT_xxx.

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>
diff --git a/include/mbedtls/legacy_or_psa.h b/include/mbedtls/legacy_or_psa.h
index f872dda..35798a5 100644
--- a/include/mbedtls/legacy_or_psa.h
+++ b/include/mbedtls/legacy_or_psa.h
@@ -64,7 +64,7 @@
  * The naming scheme for these macros is:
  *      MBEDTLS_HAS_feature_VIA_legacy_OR_PSA(_condition)
  * where:
- * - feature is expressed the same way as in PSA_WANT macros, for example:
+ * - feature is expressed the same way as in PSA_WANT_xxx macros, for example:
  *   KEY_TYPE_AES, ALG_SHA_256, ECC_SECP_R1_256;
  * - legacy is either LOWLEVEL or the name of the layer: MD, CIPHER;
  * - condition is omitted if it's based on availability, else it's