TlbTypes: Fix exception code reported for some store page fault conditions

The mode and well-formedness checks above also set fault to True, so we
end up with cases where a DataStore request uses the default load page
fault exception code. Instead, unconditionally set excStorePageFault for
DataStore, and conditionally override to excStoreCapPageFault when
appropriate, being particularly careful to ensure earlier exception
causes still take precedence.

Also restructure the InstFetch and DataLoad cases to match how DataStore
needs to look.

This fixes the rv64si-p-dirty ISA test, currently the sole failure.

src_Core/RISCY_OOO/procs/lib/TlbTypes.bsv

@@ -228,28 +228,28 @@ function TlbPermissionCheck hasVMPermission(
     // check execute/read/write permission
     case(access)
         InstFetch: begin
+            excCode = excLoadPageFault;
             if(!pte_type.executable) begin
                 fault = True;
             end
-            excCode = excLoadPageFault;
         end
         DataLoad: begin
+            excCode = excLoadPageFault;
             // need to consider mstatus.mxr bit
             if (!pte_type.readable &&
                 !(pte_type.executable && vm_info.exeReadable)) begin
                 fault = True;
             end
-            excCode = excLoadPageFault;
         end
         DataStore: begin
+            excCode = excStorePageFault;
             // store requires page to be both readable and writable
             if(!(pte_type.readable && pte_type.writable)) begin
                 fault = True;
-                excCode = excStorePageFault;
             end
             else if(cap && !pte_upper_type.cap_writable) begin
+                if (!fault) excCode = excStoreCapPageFault;
                 fault = True;
-                excCode = excStoreCapPageFault;
             end
         end
     endcase