Unconditionally compile part of the DTB code

src/startup/memory.rs

@@ -148,7 +148,6 @@ fn align_down(x: usize) -> usize {
 
 fn register_memory_from_kernel_args(args: &KernelArgs) {
     register_bootloader_areas(args.areas_base as usize, args.areas_size as usize);
-    #[cfg(dtb)]
     if let Some(dt) = args.dtb() {
         crate::dtb::register_dev_memory_ranges(&dt);
     }

src/startup/mod.rs

@@ -103,7 +103,6 @@ impl KernelArgs {
         }
     }
 
-    #[cfg(dtb)]
     pub(crate) fn dtb(&self) -> Option<fdt::Fdt<'static>> {
         if self.hwdesc_base != 0 {
             let data = unsafe {