headers: utsname.h redux

* remove asm/atomic.h inclusion from linux/utsname.h --
   not needed after kref conversion
 * remove linux/utsname.h inclusion from files which do not need it

NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however
due to some personality stuff it _is_ needed -- cowardly leave ELF-related
headers and files alone.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/utsname.h

@@ -36,7 +36,6 @@ struct new_utsname {
 #include <linux/kref.h>
 #include <linux/nsproxy.h>
 #include <linux/err.h>
-#include <asm/atomic.h>
 
 struct uts_namespace {
 	struct kref kref;