mm, memory_hotplug: drop pointless block alignment checks from __offline_pages

This function is never called from a context which would provide
misaligned pfn range so drop the pointless check.

Link: http://lkml.kernel.org/r/20181107101830.17405-4-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NOscar Salvador <osalvador@suse.de>
Reviewed-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Oscar Salvador <OSalvador@suse.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug.c

@@ -1554,12 +1554,6 @@ static int __ref __offline_pages(unsigned long start_pfn,
 	struct zone *zone;
 	struct memory_notify arg;
 
-	/* at least, alignment against pageblock is necessary */
-	if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
-		return -EINVAL;
-	if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
-		return -EINVAL;
-
 	mem_hotplug_begin();
 
 	/* This makes hotplug much easier...and readable.