kernel/vm_manager: Remove unused class variables

Over time these have fallen out of use due to refactoring, so these can
be removed.

src/core/hle/kernel/vm_manager.h

@@ -621,9 +621,6 @@ private:
     VAddr new_map_region_base = 0;
     VAddr new_map_region_end = 0;
 
-    VAddr main_code_region_base = 0;
-    VAddr main_code_region_end = 0;
-
     VAddr tls_io_region_base = 0;
     VAddr tls_io_region_end = 0;