Guard pk_opaque_rsa_decrypt() with PSA_WANT_KEY_TYPE_RSA_KEY_PAIR

Then mbedtls_pk_error_from_psa_rsa() also needs to be guarded with
PSA_WANT_KEY_TYPE_RSA_KEY_PAIR to be used by pk_opaque_rsa_decrypt()

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/library/pk_wrap.h b/library/pk_wrap.h
index 5e81a65..fc756db 100644
--- a/library/pk_wrap.h
+++ b/library/pk_wrap.h
@@ -148,9 +148,10 @@
 #if defined(MBEDTLS_PSA_CRYPTO_C)
 int mbedtls_pk_error_from_psa( psa_status_t status );
 
-#if defined(PSA_WANT_KEY_TYPE_RSA_PUBLIC_KEY)
+#if defined(PSA_WANT_KEY_TYPE_RSA_PUBLIC_KEY) ||    \
+    defined(PSA_WANT_KEY_TYPE_RSA_KEY_PAIR)
 int mbedtls_pk_error_from_psa_rsa( psa_status_t status );
-#endif
+#endif /* PSA_WANT_KEY_TYPE_RSA_PUBLIC_KEY || PSA_WANT_KEY_TYPE_RSA_KEY_PAIR */
 
 #if defined(MBEDTLS_RSA_C)
 int  mbedtls_pk_psa_rsa_sign_ext( psa_algorithm_t psa_alg_md,