x86/boot: Remove unused finalize_identity_maps()

Commit

  8570978e ("x86/boot/compressed/64: Don't pre-map memory in KASLR code")

removed all the references to finalize_identity_maps(), but neglected to
delete the actual function. Remove it.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201005151208.2212886-2-nivedita@alum.mit.edu

arch/x86/boot/compressed/ident_map_64.c

@@ -167,16 +167,6 @@ void initialize_identity_maps(void *rmode)
 	write_cr3(top_level_pgt);
 }
 
-/*
- * This switches the page tables to the new level4 that has been built
- * via calls to add_identity_map() above. If booted via startup_32(),
- * this is effectively a no-op.
- */
-void finalize_identity_maps(void)
-{
-	write_cr3(top_level_pgt);
-}
-
 static pte_t *split_large_pmd(struct x86_mapping_info *info,
 			      pmd_t *pmdp, unsigned long __address)
 {