Check the Config access protocol before use it.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15251 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/SetupBrowserDxe/Setup.c

@@ -2132,6 +2132,10 @@ SendDiscardInfoToDriver (
   EFI_IFR_TYPE_VALUE          *TypeValue;
   EFI_BROWSER_ACTION_REQUEST  ActionRequest;
 
+  if (FormSet->ConfigAccess == NULL) {
+    return;
+  }
+
   Link = GetFirstNode (&Form->StatementListHead);
   while (!IsNull (&Form->StatementListHead, Link)) {
     Question = FORM_BROWSER_STATEMENT_FROM_LINK (Link);