include/linux/mm.h: clean up obsolete check on space in page->flags

The check was intended to make sure we don't overrun page flags.  But
it's obsolete because it doesn't include LAST_CPUPID_WIDTH nor
KASAN_TAG_WIDTH.

Just remove check since we already have it covered in
linux/page-flags-layout.h (near the end of the file).

Link: http://lkml.kernel.org/r/20191208183508.89177-1-yuzhao@google.comSigned-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm.h

@@ -916,10 +916,6 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
 
 #define ZONEID_PGSHIFT		(ZONEID_PGOFF * (ZONEID_SHIFT != 0))
 
-#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
-#error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
-#endif
-
 #define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
 #define NODES_MASK		((1UL << NODES_WIDTH) - 1)
 #define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)