[Kernel] XFile: Override file position if offset is provided

src/xenia/kernel/xfile.cc

@@ -157,6 +157,10 @@ X_STATUS XFile::Read(uint32_t buffer_guest_address, uint32_t buffer_length,
                   xe::global_critical_region::AcquireDirect(),
                   buffer_guest_address, buffer_length, true, true);
             }
+
+            if (byte_offset) {
+              position_ = byte_offset;
+            }
             position_ += bytes_read;
           }
         }