sparse pointer use of zero as null

Get rid of sparse related warnings from places that use integer as NULL
pointer.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/futex.c b/kernel/futex.c
index d725676..e45a65e 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -293,7 +293,7 @@
  */
 void drop_futex_key_refs(union futex_key *key)
 {
-	if (key->both.ptr == 0)
+	if (!key->both.ptr)
 		return;
 	switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
 		case FUT_OFF_INODE:
@@ -1046,7 +1046,7 @@
  retry:
 	lock_ptr = q->lock_ptr;
 	barrier();
-	if (lock_ptr != 0) {
+	if (lock_ptr != NULL) {
 		spin_lock(lock_ptr);
 		/*
 		 * q->lock_ptr can change between reading it and