Address Scrutinice findings (#2121)

### Issues:
Addresses P188794065

### Description of changes: 
* Cleanup a few issues identified through static anaylsis

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under the terms of the Apache 2.0 license and the ISC license.

crypto/evp_extra/p_pqdsa.c

@@ -59,6 +59,7 @@ static int pkey_pqdsa_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) {
 static int pkey_pqdsa_sign_message(EVP_PKEY_CTX *ctx, uint8_t *sig,
                                      size_t *sig_len, const uint8_t *message,
                                      size_t message_len) {
+  GUARD_PTR(sig_len);
   PQDSA_PKEY_CTX *dctx = ctx->data;
   const PQDSA *pqdsa = dctx->pqdsa;
   if (pqdsa == NULL) {
@@ -71,10 +72,8 @@ static int pkey_pqdsa_sign_message(EVP_PKEY_CTX *ctx, uint8_t *sig,
 
   // Caller is getting parameter values.
   if (sig == NULL) {
-    if (sig_len != NULL) {
-      *sig_len = pqdsa->signature_len;
-      return 1;
-    }
+    *sig_len = pqdsa->signature_len;
+    return 1;
   }
 
   if (*sig_len != pqdsa->signature_len) {

crypto/pkcs8/pkcs8_x509.c

@@ -188,7 +188,7 @@ X509_SIG *PKCS8_encrypt(int pbe_nid, const EVP_CIPHER *cipher, const char *pass,
                         int pass_len_in, const uint8_t *salt, size_t salt_len,
                         int iterations, PKCS8_PRIV_KEY_INFO *p8inf) {
   size_t pass_len;
-  if (pass_len_in == -1 && pass != NULL) {
+  if (pass_len_in < 0 && pass != NULL) {
     pass_len = strlen(pass);
   } else {
     pass_len = (size_t)pass_len_in;