bpf: add parenthesis around argument of BPF_LDST_BYTES()

BPF_LDST_BYTES() does not put it's argument in parenthesis
when referencing it.  This makes it impossible to pass pointers
obtained by address-of operator (e.g. BPF_LDST_BYTES(&insn)).
Add the parenthesis.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

include/linux/filter.h

@@ -372,7 +372,7 @@ struct xdp_rxq_info;
 
 #define BPF_LDST_BYTES(insn)					\
 	({							\
-		const int __size = bpf_size_to_bytes(BPF_SIZE(insn->code)); \
+		const int __size = bpf_size_to_bytes(BPF_SIZE((insn)->code)); \
 		WARN_ON(__size < 0);				\
 		__size;						\
 	})