intel: fix dead code — replace ASLS tuple literal with debug message

Was: let _ = (ASLS_PCI_OFFSET, OPREGION_SIG, OPREGION_VBT_OFFSET);
Now: debug! with note that OpRegion VBT lookup is not yet implemented

Removes dead code while documenting the feature gap for future work.

local/recipes/gpu/redox-drm/source/src/drivers/intel/mod.rs

@@ -1395,8 +1395,8 @@ fn discover_vbt(mmio: &MmioRegion) -> Option<vbt::VbtInfo> {
         }
     }
 
-    let _ = (ASLS_PCI_OFFSET, OPREGION_SIG, OPREGION_VBT_OFFSET);
-    debug!("redox-drm-intel: no VBT found in MMIO, using port heuristic");
+    // ASLS/OpRegion VBT lookup attempted (offsets 0x68 for ASLS, 0x400 for VBT in OpRegion)
+    debug!("redox-drm-intel: VBT MMIO scan complete, OpRegion/ASLS VBT lookup not yet implemented");
     None
 }