embed/extmod/modtrezorcrypto: use mnemonic_clear where needed

embed/extmod/modtrezorcrypto/modtrezorcrypto-bip39.h

@@ -81,7 +81,9 @@ STATIC mp_obj_t mod_trezorcrypto_bip39_generate(mp_obj_t strength) {
         mp_raise_ValueError("Invalid bit strength (only 128, 160, 192, 224 and 256 values are allowed)");
     }
     const char *mnemo = mnemonic_generate(bits);
-    return mp_obj_new_str_copy(&mp_type_str, (const uint8_t *)mnemo, strlen(mnemo));
+    mp_obj_t res = mp_obj_new_str_copy(&mp_type_str, (const uint8_t *)mnemo, strlen(mnemo));
+    mnemonic_clear();
+    return res;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_bip39_generate_obj, mod_trezorcrypto_bip39_generate);
 
@@ -96,7 +98,9 @@ STATIC mp_obj_t mod_trezorcrypto_bip39_from_data(mp_obj_t data) {
         mp_raise_ValueError("Invalid data length (only 16, 20, 24, 28 and 32 bytes are allowed)");
     }
     const char *mnemo = mnemonic_from_data(bin.buf, bin.len);
-    return mp_obj_new_str_copy(&mp_type_str, (const uint8_t *)mnemo, strlen(mnemo));
+    mp_obj_t res = mp_obj_new_str_copy(&mp_type_str, (const uint8_t *)mnemo, strlen(mnemo));
+    mnemonic_clear();
+    return res;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_bip39_from_data_obj, mod_trezorcrypto_bip39_from_data);
 

vendor/trezor-crypto

@@ -1 +1 @@
-Subproject commit c316e775a2152db255ace96b6b65ac0f20525ec0
+Subproject commit d1c52401e4c76c74a10455682ace0655b7aa644c