Use clearer function name

I went for "may be" as I was thinking just checking the tag technically
does not guarantee that what follows is correct, but I was wrong:
according to ASN.1, when there are variants, the tag does distinguish
unambiguously between variants, so we can be more positive here.
(Whether the thing inside that variant is correct is a different
question.)

As a welcome side effect, this makes the name more standard hence more
readable.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/pkparse.c b/library/pkparse.c
index b0eef95..820c8d1 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -351,7 +351,7 @@
  *      Low-level ECC parsing: optional support for SpecifiedECDomain
  *
  * There are two functions here that are used by the rest of the code:
- * - pk_ecc_tag_may_be_speficied_ec_domain()
+ * - pk_ecc_tag_is_speficied_ec_domain()
  * - pk_ecc_group_id_from_specified()
  *
  * All the other functions are internal to this section.
@@ -365,7 +365,7 @@
 
 #if !defined(MBEDTLS_PK_PARSE_EC_EXTENDED)
 /* See the "real" version for documentation */
-static int pk_ecc_tag_may_be_specified_ec_domain(int tag)
+static int pk_ecc_tag_is_specified_ec_domain(int tag)
 {
     (void) tag;
     return 0;
@@ -384,7 +384,7 @@
  * Tell if the passed tag might be the start of SpecifiedECDomain
  * (that is, a sequence).
  */
-static int pk_ecc_tag_may_be_specified_ec_domain(int tag)
+static int pk_ecc_tag_is_specified_ec_domain(int tag)
 {
     return tag == (MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
 }
@@ -660,7 +660,7 @@
     /* Acceptable tags: OID for namedCurve, or specifiedECDomain */
     params->tag = **p;
     if (params->tag != MBEDTLS_ASN1_OID &&
-        !pk_ecc_tag_may_be_specified_ec_domain(params->tag)) {
+        !pk_ecc_tag_is_specified_ec_domain(params->tag)) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
                                  MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
     }