xtensa: don't clear swapper_pg_dir in paging_init

swapper_pg_dir is located in the .bss, so it's zero-initialized anyway.
With KASAN enabled paging_init will be called after KASAN
initialization, it must not erase page directory entries set up for
KASAN shadow map.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/mm/mmu.c

@@ -56,7 +56,6 @@ static void __init fixedrange_init(void)
 
 void __init paging_init(void)
 {
-	memset(swapper_pg_dir, 0, PAGE_SIZE);
 #ifdef CONFIG_HIGHMEM
 	fixedrange_init();
 	pkmap_page_table = init_pmd(PKMAP_BASE, LAST_PKMAP);