Layers: Fix intel bug introduced in commit 73d4f2f

The patch failed to mask the incoming address to the maximum physical
address.  This allowed non-canonical addresses (potentially within the
page table) to be looked up incorrectly.

Fixes #1374.

Thanks to @the-rectifier for quickly identifying the issue!

volatility3/framework/layers/intel.py

@@ -182,7 +182,7 @@ def _translate(self, offset: int) -> Tuple[int, int, str]:
 
     def _pte_pfn(self, entry: int) -> int:
         """Extracts the page frame number (PFN) from the page table entry (PTE) entry"""
-        return entry >> self.page_shift
+        return self._mask(entry, self._maxphyaddr - 1, 0) >> self.page_shift
 
     def _translate_entry(self, offset: int) -> Tuple[int, int]:
         """Translates a specific offset based on paging tables.