library: ssl: replace mbedtls_pk_can_do_ext with mbedtls_pk_can_do_psa

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 38db9cd..c6a119f 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -8147,14 +8147,14 @@
                     mbedtls_md_psa_alg_from_type(md_alg);
 
                 if (sig_alg_received == MBEDTLS_SSL_SIG_ECDSA &&
-                    !mbedtls_pk_can_do_ext(ssl->handshake->key_cert->key,
+                    !mbedtls_pk_can_do_psa(ssl->handshake->key_cert->key,
                                            PSA_ALG_ECDSA(psa_hash_alg),
                                            PSA_KEY_USAGE_SIGN_HASH)) {
                     continue;
                 }
 
                 if (sig_alg_received == MBEDTLS_SSL_SIG_RSA &&
-                    !mbedtls_pk_can_do_ext(ssl->handshake->key_cert->key,
+                    !mbedtls_pk_can_do_psa(ssl->handshake->key_cert->key,
                                            PSA_ALG_RSA_PKCS1V15_SIGN(
                                                psa_hash_alg),
                                            PSA_KEY_USAGE_SIGN_HASH)) {