When using TF-M, use the PSA_KEY_TYPE_ECC_KEY_PAIR() macro from
mbedtls_psa_parse_tls_ecc_group(), since that function is supposed to
return a psa_key_type_t. This helps to avoid any misencodings when the
return value from mbedtls_psa_parse_tls_ecc_group() is used directly as
a psa_key_type_t without additional encoding.

Fixes: 0961f312c6b0 ("Make PSA util compatible with Mbed Crypto 3.0.1")