CIFS: Include <linux/init.h> in dns_resolve.h

fs/cifs/dns_resolve.c fails to build on some architectures:

In file included from fs/cifs/dns_resolve.c:30:
fs/cifs/dns_resolve.h:27: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'cifs_init_dns_resolver'

We need to include <linux/init.h> to ensure that __init is defined.

---
 fs/cifs/dns_resolve.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

index 5d7f291..71c4769 100644
@@ -24,6 +24,7 @@
 #define _DNS_RESOLVE_H
 
 #ifdef __KERNEL__
+#include <linux/init.h>
 extern int __init cifs_init_dns_resolver(void);
 extern void cifs_exit_dns_resolver(void);
 extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr);

1.7.1