mm/mem-hotplug: replace simple_strtoull() with kstrtoull()

Use the newer and more pleasant kstrtoull() to replace
simple_strtoull(), because simple_strtoull() is marked for obsoletion.

Signed-off-by: Zhang Zhen <[e-mail]>
Acked-by: David Rientjes <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/base/memory.c

···
 	int i, ret;
 	unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
 
-	phys_addr = simple_strtoull(buf, NULL, 0);
+	ret = kstrtoull(buf, 0, &phys_addr);
+	if (ret)
+		return ret;
 
 	if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
 		return -EINVAL;