h8300: convert to setup_initial_init_mm()

Use setup_initial_init_mm() helper to simplify code.

Link: https://lkml.kernel.org/r/20210608083418.137226-7-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/h8300/kernel/setup.c

@@ -95,10 +95,7 @@ void __init setup_arch(char **cmdline_p)
 {
 	unflatten_and_copy_device_tree();
 
-	init_mm.start_code = (unsigned long) _stext;
-	init_mm.end_code = (unsigned long) _etext;
-	init_mm.end_data = (unsigned long) _edata;
-	init_mm.brk = (unsigned long) 0;
+	setup_initial_init_mm(_stext, _etext, _edata, NULL);
 
 	pr_notice("\r\n\nuClinux " CPU "\n");
 	pr_notice("Flat model support (C) 1998,1999 Kenneth Albanowski, D. Jeff Dionne\n");