netfilter: uapi: Avoid undefined left-shift in xt_sctp.h

With 'bytes(__u32)' being 32, a left-shift of 31 may happen which is
undefined for the signed 32-bit value 1. Avoid this by declaring 1 as
unsigned.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter/xt_sctp.h

@@ -41,19 +41,19 @@ struct xt_sctp_info {
 #define SCTP_CHUNKMAP_SET(chunkmap, type) 		\
 	do { 						\
 		(chunkmap)[type / bytes(__u32)] |= 	\
-			1 << (type % bytes(__u32));	\
+			1u << (type % bytes(__u32));	\
 	} while (0)
 
 #define SCTP_CHUNKMAP_CLEAR(chunkmap, type)		 	\
 	do {							\
 		(chunkmap)[type / bytes(__u32)] &= 		\
-			~(1 << (type % bytes(__u32)));	\
+			~(1u << (type % bytes(__u32)));	\
 	} while (0)
 
 #define SCTP_CHUNKMAP_IS_SET(chunkmap, type) 			\
 ({								\
 	((chunkmap)[type / bytes (__u32)] & 		\
-		(1 << (type % bytes (__u32)))) ? 1: 0;	\
+		(1u << (type % bytes (__u32)))) ? 1: 0;	\
 })
 
 #define SCTP_CHUNKMAP_RESET(chunkmap) \