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/kexec.c b/kernel/kexec.c
index 7885269..e9f1b4e 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -785,7 +785,7 @@
 		size_t uchunk, mchunk;
 
 		page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
-		if (page == 0) {
+		if (!page) {
 			result  = -ENOMEM;
 			goto out;
 		}
@@ -844,7 +844,7 @@
 		size_t uchunk, mchunk;
 
 		page = pfn_to_page(maddr >> PAGE_SHIFT);
-		if (page == 0) {
+		if (!page) {
 			result  = -ENOMEM;
 			goto out;
 		}