Remove some impossible null checks

The CERT structure is never null.

Change-Id: I92436e1ad6156a9f79d30f4f5e989022e8fd0e9d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/66371
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

ssl/ssl_lib.cc

diff --git a/ssl/ssl_lib.cc b/ssl/ssl_lib.cc
index 23fdccb..81a9807 100644
--- a/ssl/ssl_lib.cc
+++ b/ssl/ssl_lib.cc
@@ -2509,21 +2509,13 @@
 EVP_PKEY *SSL_get_privatekey(const SSL *ssl) {
   if (!ssl->config) {
     assert(ssl->config);
-    return NULL;
+    return nullptr;
   }
-  if (ssl->config->cert != NULL) {
-    return ssl->config->cert->privatekey.get();
-  }
-
-  return NULL;
+  return ssl->config->cert->privatekey.get();
 }
 
 EVP_PKEY *SSL_CTX_get0_privatekey(const SSL_CTX *ctx) {
-  if (ctx->cert != NULL) {
-    return ctx->cert->privatekey.get();
-  }
-
-  return NULL;
+  return ctx->cert->privatekey.get();
 }
 
 const SSL_CIPHER *SSL_get_current_cipher(const SSL *ssl) {