sim: Get rid of the now unused System::getPageBytes method.

Change-Id: I90bd3f3468e0835b882de1b31df8481da04f5af1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50764
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/sim/system.hh

@@ -392,11 +392,6 @@ class System : public SimObject, public PCEventScope
         return params().byte_order;
     }
 
-     /**
-     * Get the page bytes for the ISA.
-     */
-    Addr getPageBytes() const { return TheISA::PageBytes; }
-
     /**
      * The thermal model used for this system (if any).
      */